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Grey, Joanna, and Kym Winter. "Patient quality of life and prognosis in multiple endocrine neoplasia type 2." Endocrine-Related Cancer 25, no. 2 (2018): T69—T77. http://dx.doi.org/10.1530/erc-17-0335.
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Multiple endocrine neoplasia type 2 (MEN2) refers to the autosomal-dominant neuroendocrine tumour syndromes, MEN type 2A (MEN2A) and MEN type 2B (MEN2B). They are typified by the development of medullary thyroid cancer (MTC), phaeochromocytoma and parathyroid hyperplasia in MEN2A and MTC, phaeochromocytomas, ganglioneuromatosis and skeletal abnormalities in MEN2B. The aggressiveness of MTC is variable according to genotype, and although it is still the major cause of mortality in both conditions, prognosis has improved dramatically in those diagnosed and treated at a young age thanks to predictive genetic testing. Nevertheless, metastatic MTC, ganglioneuromatosis and a variety of other negative clinical and psychosocial impacts on quality of life and/or prognosis in MEN2 persist. In the absence, at the time of writing, of any large-scale research into quality of life specifically in MEN2, this review includes data from patient surveys and anonymised patient anecdotes from the records of the Association for Multiple Endocrine Neoplasia Disorders (AMEND), for whom the authors work. We recommend that these patients are cared for only in centres of expertise able to provide expert diagnosis, treatment and continuity of care, including psychological and transition support. Only in this way can the clinical advances of the last two and half decades be built upon further to ensure that the care of these complex, lifelong patients can be considered truly holistic.
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Shahnazari, Banafshe, Aria Aghamaleki, Bagher Larijani, Mohammad Reza Mohajeri Tehrani, Hasan Rafati, and Abdolreza Babamahmoodi. "A Case of Multiple Endocrine Neoplasia Type 2B and Gangliomatosis of Gastrointestinal Tract." Case Reports in Medicine 2012 (2012): 1–4. http://dx.doi.org/10.1155/2012/491054.
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Multiple endocrine neoplasia type 2 (MEN2) is a rare familial syndrome caused by mutations in the RET protooncogene and it is transmitted as an autosomal dominant trait. The underlying problem for all the MEN syndromes is failure of a tumour suppressor gene. The genetic defect in MEN2 is on chromosome 10 (10q11.2) and has also been identified both for MEN2A and MEN2B. The reported patient is an 18-year-old girl presented with long-term diarrhea and enterocutaneous fistula. Her thyroid nodules, marfanoid habitus and bumpy lips, were also highly suggestive for MEN2B.
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Schaaf, Ludwig, and Friedhelm Raue. "Multiple endokrine Neoplasie." DMW - Deutsche Medizinische Wochenschrift 142, no. 18 (2017): 1379–89. http://dx.doi.org/10.1055/s-0043-109522.
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AbstractMultiple endocrine neoplasia type 1 and 2 are hereditary cancer syndromes. They are characterized by the occurrence of many benign and malignant tumor types, in MEN1 parathyroid tumors, pituitary tumors, and pancreas tumors, in MEN2 medullary thyroid carcinoma, pheochromocytoma, and parathyroid tumors. The autosomal dominant inherited tumor syndromes are caused by mutations in the MEN1 gene, a tumor suppressor gene, and mutations in the RET gene, an activated oncogene, in MEN2. The clinical expression of the different tumors can vary within and between families, with a good genotype-phenotype correlation in MEN2. Early diagnosis and therapy is possible by using biochemical and imaging screening in the families. Early thyroidectomy in young patients with MEN2 results in a high cure rate of MTC.
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Das, Tirtha K., and Ross L. Cagan. "Non-mammalian models of multiple endocrine neoplasia type 2." Endocrine-Related Cancer 25, no. 2 (2018): T91—T104. http://dx.doi.org/10.1530/erc-17-0411.
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Twenty-five years ago, RET was identified as the primary driver of multiple endocrine neoplasia type 2 (MEN2) syndrome. MEN2 is characterized by several transformation events including pheochromocytoma, parathyroid adenoma and, especially penetrant, medullary thyroid carcinoma (MTC). Overall, MTC is a rare but aggressive type of thyroid cancer for which no effective treatment currently exists. Surgery, radiation, radioisotope treatment and chemotherapeutics have all shown limited success, and none of these approaches have proven durable in advanced disease. Non-mammalian models that incorporate the oncogenic RET isoforms associated with MEN2 and other RET-associated diseases have been useful in delineating mechanisms underlying disease progression. These models have also identified novel targeted therapies as single agents and as combinations. These studies highlight the importance of modeling disease in the context of the whole animal, accounting for the complex interplay between tumor and normal cells in controlling disease progression as well as response to therapy. With convenient access to whole genome sequencing data from expanded thyroid cancer patient cohorts, non-mammalian models will become more complex, sophisticated and continue to complement future mammalian studies. In this review, we explore the contributions of non-mammalian models to our understanding of thyroid cancer including MTC, with a focus onDanio rerioandDrosophila melanogaster(fish and fly) models.
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Machens, Andreas, and Henning Dralle. "Advances in risk-oriented surgery for multiple endocrine neoplasia type 2." Endocrine-Related Cancer 25, no. 2 (2018): T41—T52. http://dx.doi.org/10.1530/erc-17-0202.
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Genetic association studies hinge on definite clinical case definitions of the disease of interest. This is why more penetrant mutations were overrepresented in early multiple endocrine neoplasia type 2 (MEN2) studies, whereas less penetrant mutations went underrepresented. Enrichment of genetic association studies with advanced disease may produce a flawed understanding of disease evolution, precipitating far-reaching surgical strategies like bilateral total adrenalectomy and 4-gland parathyroidectomy in MEN2. The insight into the natural course of the disease gleaned over the past 25 years caused a paradigm shift in MEN2: from the removal of target organs at the expense of greater operative morbidity to close biochemical surveillance and targeted resection of adrenal tumors and hyperplastic parathyroid glands. The lead time provided by early identification of asymptomatic MEN2 carriers under biochemical surveillance delimits a ‘window of opportunity’, within which (i) pre-emptive total thyroidectomy alone is adequate, circumventing morbidity attendant to central node dissection; (ii) subtotal ‘tissue-sparing’ adrenalectomy is sufficient, trading the risk of steroid dependency for the risk of a second pheochromocytoma in the adrenal remnant and (iii) parathyroidectomy is limited to enlarged glands, trading the risk of postoperative hypoparathyroidism for the risk of leaving behind hyperactive parathyroid glands. Future research should delineate further the mutation-specific, age-dependent penetrance of pheochromocytoma and primary hyperparathyroidism to refine the risk-oriented approach to MEN2. The sweeping changes in the management of MEN2 since the new millenium hold the hope that death and major morbidity from this uncommon disease can be eliminated in our lifetime.
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Castellone, Maria Domenica, and Rosa Marina Melillo. "RET-mediated modulation of tumor microenvironment and immune response in multiple endocrine neoplasia type 2 (MEN2)." Endocrine-Related Cancer 25, no. 2 (2018): T105—T119. http://dx.doi.org/10.1530/erc-17-0303.
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Medullary thyroid carcinomas (MTC) arise from thyroid parafollicular, calcitonin-producing C-cells and can occur either as sporadic or as hereditary diseases in the context of familial syndromes, including multiple endocrine neoplasia 2A (MEN2A), multiple endocrine neoplasia 2B (MEN2B) and familial MTC (FMTC). In a large fraction of sporadic cases, and virtually in all inherited cases of MTC, activating point mutations of theRETproto-oncogene are found.RETencodes for a receptor tyrosine kinase protein endowed with transforming potential on thyroid parafollicular cells. As in other cancer types, microenvironmental factors play a critical role in MTC. Tumor-associated extracellular matrix, stromal cells and immune cells interact and influence the behavior of cancer cells both in a tumor-promoting and in a tumor-suppressing manner. Several studies have shown that, besides the neoplastic transformation of thyroid C-cells, a profound modification of tumor microenvironment has been associated to the RET FMTC/MEN2-associated oncoproteins. They influence the surrounding stroma, activating cancer-associated fibroblasts (CAFs), promoting cancer-associated inflammation and suppressing anti-cancer immune response. These mechanisms might be exploited to develop innovative anti-cancer therapies and novel prognostic tools in the context of familial, RET-associated MTC.
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Igarashi, Takehito. "Recent Progress in Multiple Endocrine Neoplasia Type 2." Nihon Ika Daigaku Igakkai Zasshi 11, no. 1 (2015): 6–11. http://dx.doi.org/10.1272/manms.11.6.
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Plaza-Menacho, Iván. "Structure and function of RET in multiple endocrine neoplasia type 2." Endocrine-Related Cancer 25, no. 2 (2018): T79—T90. http://dx.doi.org/10.1530/erc-17-0354.
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It has been twenty-five years since the discovery of oncogenic germline RET mutations as the cause of multiple endocrine neoplasia type 2 (MEN2). Intensive work over the last two and a half decades on RET genetics, signaling and cell biology has provided the current bases for the genotype–phenotype and functional correlations within this cancer syndrome. On the contrary, the structural and molecular basis for RET tyrosine kinase domain activation and oncogenic deregulation has remained largely elusive. Recent studies with a strong crystallographic and biochemical focus have started to elucidate key insights into such molecular and atomic details revealing unexpected and private mechanisms of actions and molecular determinants not previously envisioned. This review focuses on the structure and function of the RET receptor, and in particular, on what a more detailed view of the protein itself and what the current structural and molecular information tell us about the genotype and phenotype relationships in the cancer syndrome MEN2.
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Kruckeberg, Kent E., and Stephen N. Thibodeau. "Pyrosequencing Technology as a Method for the Diagnosis of Multiple Endocrine Neoplasia Type 2." Clinical Chemistry 50, no. 3 (2004): 522–29. http://dx.doi.org/10.1373/clinchem.2003.027128.
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Abstract Background: Multiple endocrine neoplasia type 2 (MEN2) is a cancer syndrome with well-characterized causative mutations. Missense mutations in ∼15 codons of the RET gene have been linked to disease phenotypes in the vast majority of cases. These missense mutations range from very simple single nucleotide base changes to more numerous changes at a given codon; they therefore are often tested for by more than one DNA-based diagnostic method. We developed and evaluated a Pyrosequencing™ technology-based approach for MEN2 mutation testing that allows both simple and complex mutations to be analyzed on one platform. Methods: Archived DNA from peripheral blood of patients referred to the Mayo Clinic Molecular Genetics laboratory for MEN2 testing was selected. One to all of codons 609, 611, 618, 620, 630, 634, 768, 804, and 918 were analyzed by Pyrosequencing technology to match the original analysis of each patient. Template PCRs were set up using an automated liquid handler; the subsequent post-PCR preparation step was performed manually, and the sequencing was performed by a PSQ 96 instrument. Samples were tested in batch sizes expected to occur routinely. Results: We analyzed samples from 217 patients who previously tested negative for MEN2 and 230 patients who previously tested positive, for a total of 1449 sequencing reactions. One discrepant result was found (100% concordant for negatives and 99.6% concordant for positives). A total of 37 unique mutations or alterations of unknown significance were analyzed. Conclusion: Pyrosequencing technology offers an accurate, nonisotopic, simple, and rapid method for the analysis of DNA from patients suspected of having MEN2.
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Ilanchezhian, Maran, Sophia Khan, Christian Okafor, John Glod, and Jaydira Del Rivero. "Update on the Treatment of Medullary Thyroid Carcinoma in Patients with Multiple Endocrine Neoplasia Type 2." Hormone and Metabolic Research 52, no. 08 (2020): 588–97. http://dx.doi.org/10.1055/a-1145-8479.
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AbstractMedullary Thyroid Carcinoma (MTC) is a rare neuroendocrine cancer that accounts for 1–2% of thyroid cancers in the United States (U.S.). While most cases are sporadic, 25% of MTC cases are hereditary. These hereditary cases occur in the setting of Multiple Endocrine Neoplasia Type 2A (MEN2A) or 2B (MEN2B) driven by mutations in the Rearranged during Transfection RET proto-oncogene. This article discusses hereditary MTC in the setting of MEN2 and the treatment options available for it. The first line treatment for this disease is typically a total thyroidectomy and tyrosine kinase inhibitors. Two tyrosine kinase inhibitors, vandetanib and cabozantinib, have been approved for treatment of advanced MTC, but options beyond those are limited. However, several promising treatments are being studied, which are discussed in this review.
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Grubbs, Elizabeth, Daniel Halperin, Steven G. Waguespack, and Robert F. Gagel. "HEREDITARY ENDOCRINE TUMOURS: CURRENT STATE-OF-THE-ART AND RESEARCH OPPORTUNITIES: History of the multiple endocrine neoplasia workshops and overview of MEN2019." Endocrine-Related Cancer 27, no. 8 (2020): E1—E5. http://dx.doi.org/10.1530/erc-20-0201.
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The multiple endocrine neoplasia (MEN) workshops had their beginnings at Queen’s University in Kingston, Ontario in June 1984. This initial meeting brought clinicians and scientists together to focus on mapping the gene for multiple endocrine neoplasia type 2 (MEN2). These efforts culminated in the identification of the RET protooncogene as the causative gene a decade later. Over the next 35 years there were a total of 16 international workshops focused on the several MEN syndromes. Importantly, these workshops were instrumental in efforts to define the molecular basis for multiple endocrine neoplasia type 1 (MEN1), MEN2, von Hippel-Lindau disease (VHL), Carney Complex, hereditary pheochromocytoma and hyperparathyroidism. In this same spirit some 150 scientists and clinicians met at MD Anderson Cancer Center, 27–29 March 2019, for the 16th International Workshop on Multiple Endocrine Neoplasia (MEN2019). Appropriate to its location in a cancer centre, the workshop focused on important issues in the causation and treatment of malignant aspects of the MEN syndromes: medullary thyroid carcinoma, pancreatic neuroendocrine tumours, malignant pheochromocytoma and parathyroid carcinoma. Workshops at the meeting focused on a better understanding of how the identified molecular defects in these genetic syndromes lead to transformation, how to apply targeted kinase inhibitors and immunotherapy to treat these tumours and important clinical management issues. This issue of Endocrine-Related Cancer describes these discussions and recommendations.
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Bajaj, Anubha. "The Genetic Multiplicity- Multiple Endocrine Neoplasia type I." International Journal of Infection Prevention 1, no. 2 (2020): 1–13. http://dx.doi.org/10.14302/issn.2690-4837.ijip-20-3176.
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Multiple endocrine neoplasia type 1 (MEN1) is a syndrome emerging from characteristic mutations of MEN1 gene with concurrently enunciated multiple endocrine and tumours and associated non-endocrine neoplasm. Previously designated as Werner’s syndrome, MEN1 syndrome denominates genomic mutation within chromosome 11q13 or a tumour suppressor gene with a distinctive protein product nomenclated as “menin”. MEN1 syndrome demonstrates an autosomal dominant pattern of disease inheritance where genomic mutations delineate a comprehensive (100%) disease penetrance. MEN1 gene was initially identified in 1997 upon chromosome 11q13. Although twelve genetic mutations were primarily identified, currently beyond eighteen hundred genomic mutations are scripted1, 2. MEN1 syndrome is comprised of diverse combination of twenty or more endocrine and non-endocrine tumours exemplifying a classic triad of pituitary, parathyroid and pancreatic neoplasm. Diverse non endocrine tumours enunciated with MEN1 syndrome are denominated with meningioma, ependymoma or angiofibroma1, 2. Endocrine tumours are discerned on account of excessive hormonal secretion engendered from various neoplasm or on account of neoplastic evolution. Approximately 10% instances can occur due to a de-novo genomic variant. Offspring of an individual with MEN1 syndrome quantifies a 50% possibility of inheriting the genomic variant. Cogent prenatal diagnosis can be determined in instances where specific genomic variant of a particular family is known. Physical, psychological and social restrictions are prevalent with MEN1 syndrome. Heterozygotes with MEN1 genetic variant are denominated as carriers and manifest a two- fold possible mortality1, 2.
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Sriphrapradang, Chutintorn, Kitjapong Choopun, Atchara Tunteeratum, and Thanyachai Sura. "Genotype-Phenotype Correlation in Patients With Germline Mutations of VHL, RET, SDHB, and SDHD Genes: Thai Experience." Clinical Medicine Insights: Endocrinology and Diabetes 10 (January 1, 2017): 117955141770512. http://dx.doi.org/10.1177/1179551417705122.
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Mutations in the VHL, RET, SDHB, and SDHD genes are responsible for von Hippel-Lindau (VHL) disease, multiple endocrine neoplasia type 2 (MEN2), and familial paraganglioma, respectively. However, genotype-phenotype correlation data are lacking in Southeast Asia. A retrospective medical chart review was performed on patients referred to the genetics service. We found 35 patients diagnosed with clinical syndromes (16 VHL, 9 MEN2, 9 paragangliomas, and 1 neurofibromatosis type 1). In patients with VHL, 5 known VHL mutations were identified: p.Trp88X, p.Ile151Thr, p.Arg161X, p.Arg167Gln, and p.Leu178Arg. The most frequent RET mutations in patients with MEN2A occurred at codon 634 on exon 11: p.Cys634Tyr, p.Cys634Trp, and p.Cys634Arg. A patient with MEN2B had p.Met918Thr RET mutation. Approximately, 90% of patients with MEN2 had medullary thyroid carcinoma. Pheochromocytoma was found in 55.6% of patients with MEN2, and 60% of them had bilateral lesions. One patient with malignant thoracic paraganglioma had p.Arg46X mutation of SDHB. This study provides mutation phenotypes that offer a useful tool for clinicians and patients to stratify disease risks and tailor screening programs.
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Santos, Marcelo A. C. G. dos, Elisangela Pereira de S. Quedas, Rodrigo de Almeida Toledo, Delmar M. Lourenço-Júnior, and Sergio Pereira de A. Toledo. "Screening of RET gene mutations in multiple endocrine neoplasia type-2 using Conformation Sensitive Gel Electrophoresis (CSGE)." Arquivos Brasileiros de Endocrinologia & Metabologia 51, no. 9 (2007): 1468–76. http://dx.doi.org/10.1590/s0004-27302007000900009.
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Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (~ 95%) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.
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Brouwers, Frederieke M., Sven Gläsker, Amanda F. Nave, et al. "Proteomic profiling of von Hippel–Lindau syndrome and multiple endocrine neoplasia type 2 pheochromocytomas reveals different expression of chromogranin B." Endocrine-Related Cancer 14, no. 2 (2007): 463–71. http://dx.doi.org/10.1677/erc-06-0038.
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Pheochromocytomas are catecholamine-producing tumors that can occur in the context of von Hippel–Lindau syndrome (VHL) and multiple endocrine neoplasia type 2 (MEN2). Pheochromocytomas in these two syndromes differ in histopathological features, catecholamine metabolism, and clinical phenotype. To further investigate the nature of these differences, we compared the global protein expressions of 8 MEN2A-associated pheochromocytomas with 11 VHL-associated pheochromocytomas by two-dimensional gel electrophoresis proteomic profiling followed by sequencing and identification of differentially expressed proteins. Although both types of pheochromocytoma shared similarities in their protein expression patterns, the expression of several proteins was distinctly different between VHL- and MEN2A-associated pheochromocytomas. We identified several of these differentially expressed proteins. One of the proteins with higher expression in MEN2-associated tumors was chromogranin B, of which the differential expression was confirmed by western blot analysis. Our results expand the evidence for proteomic differences between these two tumor entities, and suggest that VHL-associated pheochromocytomas may be deficient in fundamental machinery for catecholamine storage. In light of these new findings, as well as existing evidence for differences between both types of pheochromocytomas, we propose that these tumors may have different developmental origins.
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Pozhar, V. I., O. V. Doroshenko, and M. I. Shevchuk. "MULTIPLE ENDOCRINE NEOPLASIA IN PRACTICE OF PRIMARY CARE AND FAMILY PHYISICIANS." International Medical Journal, no. 1 (March 5, 2020): 11–15. http://dx.doi.org/10.37436/2308-5274-2020-1-2.
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Multiple endocrine neoplasia is characterized with a predisposition to tumors involving two or more endocrine glands. The four main forms of the disease are inherited as an autosomal dominant syndrome or may occur sporadically. In addition to these four forms, six other syndromes are associated with the presence of multiple endocrine and other neoplasms of the organs: hyperparathyroidism − jaw tumors, Carney complex, von Hippel−Lindau disease, neurofibromatosis type 1, Cowden syndrome and McCune − Albright syndrome. The diagnosis of multiple endocrine neoplasia syndrome can be established in humans by one of the three available criteria: clinical features, family history, genetic analysis. Mutation analysis during these syndromes is useful in clinical practice to confirm the clinical diagnosis; identifying family members who tolerate the mutation and need to be screened, and identifying family members who do not tolerate the mutation. Syndrome of multiple endocrine neoplasia (Wermer syndrome) is characterized by the presence of a triad of tumors, including tumors of the parathyroid glands, pheochromocytoma and tumors of the parathyroid gland. It occurs less frequently in combination with Hirschsprung's disease, caused by the absence of vegetative ganglion cells in the intestine terminal parts, that leads to colonic enlargement, severe constipation and obstruction. This syndrome may be associated with cutaneous lichen amyloidosis, the clinical manifestations of which are pruritus and lichenoid lesions, usually located in the upper back. A clinical case of MEN2 syndrome in a 52−year−old patient is presented. It is noted that for such patients, in addition to timely syndromic rather than component diagnosis of this endocrine multipathology, the spread of neoplastic process in medullary thyroid cancer to its capsule and surrounding tissues, as well as the presence of metastases in peripheral lymph nodes are important. As a rule, such patients cannot be timely cured. Key words: multiple endocrine neoplasia, endocrine tumors, genetic analysis, family history.
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Giani, Carlotta, Teresa Ramone, Cristina Romei, et al. "A New MEN2 Syndrome with Clinical Features of Both MEN2A and MEN2B Associated with a New RET Germline Deletion." Case Reports in Endocrinology 2020 (July 29, 2020): 1–7. http://dx.doi.org/10.1155/2020/4147097.
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Background. Multiple endocrine neoplasia type 2 (MEN2) is a hereditary cancer syndrome caused by RET proto-oncogene mutation. Two different clinical variants of MEN2 are known (MEN2A and MEN2B): medullary thyroid carcinoma (MTC) almost always present and associated with pheochromocytoma (Pheo), and primary hyperparathyroidism (HPTH) in MEN2A and with Pheo and other nonendocrine diseases in MEN2B. Case Report. A 7-year-old girl, previously treated for a pelvic plexiform neurofibroma, arrived at our observation with a peculiar MEN2B syndrome and with HPTH. The neck ultrasound showed bilateral thyroid nodules, local lymph node lesions, and a suspicious left hyperplastic parathyroid. The CT scan showed a megacolon and described the persistence of the pelvic tumor. A new RET germline deletion in exon 11 (c.1892_1899delCGAGCT; p.Glu632_Leu633del) was found. She underwent total thyroidectomy, central compartment and latero-cervical lymph node dissection, and neck exploration for primary HPTH. The histology confirmed bilateral MTC, multiple lymph node metastases, a hyperplastic parathyroid, and a parathyroid adenoma. Conclusions. This is the first case of a complex syndrome characterized by peculiar features of MEN2B, without Pheo but with a pelvic plexiform neurofibroma and with HPTH, which is typical of MEN2A. A “de novo” new germline RET deletion located in exon 11 was found.
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Rumiantsev, Pavel O., Konstantin Y. Slashchuk, Sergey V. Korenev, Andrei G. Goncharov, Dmitriy G. Beltsevich, and Olga S. Chukhacheva. "Interdisciplinary data bank in oncoendocrinology. Medullary thyroid cancer and type 2 multiple endocrine neoplasia syndromes." Endocrine Surgery 13, no. 3 (2020): 105–17. http://dx.doi.org/10.14341/serg11270.
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Medullary thyroid cancer (MTC) is about 5% of all thyroid carcinomas and is hereditary in 2030% of cases. Multiple endocrine neoplasia syndrome type 2 (MEN2), in addition to medullary thyroid cancer, may include pheochromocytoma, hyperparathyroidism, and some other manifestations.
 The multidisciplinary data bank (MDB) developed by us is a specialized resource for storing, accumulating and subsequent analysis of data on patients with MTC and MEN2 syndromes. The MDB allows you to collect data from any sources (primary care, medical institutions at various levels, federal centers) and provides internal automated control of the quality and quantity of input data. It is necessary to keep a record of such data to improve the efficiency of diagnostics, treatment and rehabilitation of patients.
 MDB is an integrated digital platform containing reference materials for doctors, which allows combining evidence-based clinical experience in patients, and provides the opportunity for expert support of medical decisions. In the long run, it will help us organize digitally stored data for machine learning and lays the groundwork for the development of artificial neural networks.
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Matsushita, Rie, Keisuke Nagasaki, Tadayuki Ayabe, et al. "Present status of prophylactic thyroidectomy in pediatric multiple endocrine neoplasia 2: a nationwide survey in Japan 1997–2017." Journal of Pediatric Endocrinology and Metabolism 32, no. 6 (2019): 585–95. http://dx.doi.org/10.1515/jpem-2018-0444.
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Abstract Background In Japan, prophylactic thyroidectomy involves out-of-pocket expense. The American Thyroid Association (ATA) recommends prophylactic thyroidectomy for medullary thyroid carcinoma (MTC) during early childhood in patients with multiple endocrine neoplasia type 2 (MEN2). The ATA reports a high frequency of postoperative complications in childhood, which also influenced the delay of prophylactic thyroidectomy in Japan. Methods This retrospective study of multiple medical centers in Japan included individuals aged <20 years diagnosed with germline RET mutations between 1997 and 2017. The onset and onset possibility were defined based on confirmed lesions or calcitonin levels. The definition of risk and prophylactic thyroidectomy were based on the ATA 2015 revised guideline. Results Twenty-one patients with MEN2 were enrolled (highest risk, n = 5; high risk, n = 5; and moderate risk, n = 11). The cumulative incidence of the onset/onset possibility reached 50% at 5 and 8 years and 100% at 9 years and 17 years in high- and moderate-risk patients, respectively. Of 7 patients with MEN2A, 71% underwent prophylactic thyroidectomy. Only one 5-year-old patient (C634Y) had increased serum calcitonin level after prophylactic thyroidectomy in the MEN2A group. The only permanent complication, which did not occur in patients who underwent total thyroidectomy alone, was hypoparathyroidism (33% of patients). This permanent complication occurred with clinically developed MTC. No permanent postoperative complications occurred in patients aged 5–6 years. Conclusions Prophylactic thyroidectomy reduces recurrence and postoperative complications in pediatric patients with MEN2. Early thyroidectomy based on only calcitonin level could possibly reduce thyroidectomy delay.
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Marini, Francesca, Francesca Giusti, Francesco Tonelli, and Maria Luisa Brandi. "Pancreatic Neuroendocrine Neoplasms in Multiple Endocrine Neoplasia Type 1." International Journal of Molecular Sciences 22, no. 8 (2021): 4041. http://dx.doi.org/10.3390/ijms22084041.
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Pancreatic neuroendocrine tumors (pNETs) are a rare group of cancers accounting for about 1–2% of all pancreatic neoplasms. About 10% of pNETs arise within endocrine tumor syndromes, such as Multiple Endocrine Neoplasia type 1 (MEN1). pNETs affect 30–80% of MEN1 patients, manifesting prevalently as multiple microadenomas. pNETs in patients with MEN1 are particularly difficult to treat due to differences in their growth potential, their multiplicity, the frequent requirement of extensive surgery, the high rate of post-operative recurrences, and the concomitant development of other tumors. MEN1 syndrome is caused by germinal heterozygote inactivating mutation of the MEN1 gene, encoding the menin tumor suppressor protein. MEN1-related pNETs develop following the complete loss of function of wild-type menin. Menin is a key regulator of endocrine cell plasticity and its loss in these cells is sufficient for tumor initiation. Somatic biallelic loss of wild-type menin in the neuroendocrine pancreas presumably alters the epigenetic control of gene expression, mediated by histone modifications and DNA hypermethylation, as a driver of MEN1-associated pNET tumorigenesis. In this light, epigenetic-based therapies aimed to correct the altered DNA methylation, and/or histone modifications might be a possible therapeutic strategy for MEN1 pNETs, for whom standard treatments fail.
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Imai, Tsuneo, Shinya Uchino, Takahiro Okamoto, et al. "High penetrance of pheochromocytoma in multiple endocrine neoplasia 2 caused by germ line RET codon 634 mutation in Japanese patients." European Journal of Endocrinology 168, no. 5 (2013): 683–87. http://dx.doi.org/10.1530/eje-12-1106.
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ObjectiveThe precise penetrance of pheochromocytoma (PHEO) in multiple endocrine neoplasia type 2 (MEN2) has not been reported in a large cohort. In this study, we aimed to clarify the codon-specific penetrance of PHEO in MEN2.DesignWe established a study group designated the ‘MEN Consortium of Japan’ in 2008 and asked physicians and surgeons to provide clinical and genetic information on patients they had treated up to 2011.MethodsData were collected on patients identified as carriers of the RET mutation or diagnosed with medullary thyroid carcinoma (MTC) and/or PHEO with family history from 52 institutions all over Japan.ResultsOf 493 registered MEN2 patients, RET mutation data were available for 390. Of these, 144developed PHEOs, while 246 did not. The penetrance of PHEO was 25% by age 30 years, 52% by age 50 years, and 88% by age 77 years in RET mutation carriers with a codon 634 mutation. All patients with a codon 918 mutation (MEN2B) developed PHEO by age 56 years. Less than 32%penetrance of PHEO was seen in patients with mutations at codons other than 634 and 918.ConclusionsMost patients with a codon 634 mutation develop PHEOs as well as MTC during their lifetime.
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Li, Yulong, and William F. Simonds. "Endocrine neoplasms in familial syndromes of hyperparathyroidism." Endocrine-Related Cancer 23, no. 6 (2016): R229—R247. http://dx.doi.org/10.1530/erc-16-0059.
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Familial syndromes of hyperparathyroidism, including multiple endocrine neoplasia type 1 (MEN1), multiple endocrine neoplasia type 2A (MEN2A), and the hyperparathyroidism-jaw tumor (HPT-JT), comprise 2–5% of primary hyperparathyroidism cases. Familial syndromes of hyperparathyroidism are also associated with a range of endocrine and nonendocrine tumors, including potential malignancies. Complications of the associated neoplasms are the major causes of morbidities and mortalities in these familial syndromes, e.g., parathyroid carcinoma in HPT-JT syndrome; thymic, bronchial, and enteropancreatic neuroendocrine tumors in MEN1; and medullary thyroid cancer and pheochromocytoma in MEN2A. Because of the different underlying mechanisms of neoplasia, these familial tumors may have different characteristics compared with their sporadic counterparts. Large-scale clinical trials are frequently lacking due to the rarity of these diseases. With technological advances and the development of new medications, the natural history, diagnosis, and management of these syndromes are also evolving. In this article, we summarize the recent knowledge on endocrine neoplasms in three familial hyperparathyroidism syndromes, with an emphasis on disease characteristics, molecular pathogenesis, recent developments in biochemical and radiological evaluation, and expert opinions on surgical and medical therapies. Because these familial hyperparathyroidism syndromes are associated with a wide variety of tumors in different organs, this review is focused on those endocrine neoplasms with malignant potential.
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Jimenez, Camilo, and Robert F. Gagel. "Genetic testing in endocrinology: lessons learned from experience with multiple endocrine neoplasia type 2 (MEN2)." Growth Hormone & IGF Research 14 (June 2004): 150–57. http://dx.doi.org/10.1016/j.ghir.2004.03.033.
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Redaelli, Sara, Ivan Plaza-Menacho, and Luca Mologni. "Novel targeted therapeutics for MEN2." Endocrine-Related Cancer 25, no. 2 (2018): T53—T68. http://dx.doi.org/10.1530/erc-17-0297.
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The rearranged during transfection (RET) proto-oncogene was recognized as the multiple endocrine neoplasia type 2 (MEN2) causing gene in 1993. Since then, much effort has been put into a clear understanding of its oncogenic signaling, its biochemical function and ways to block its aberrant activation in MEN2 and related cancers. Several small molecules have been designed, developed or redirected as RET inhibitors for the treatment of MEN2 and sporadic MTC. However, current drugs are mostly active against several other kinases, as they were not originally developed for RET. This limits efficacy and poses safety issues. Therefore, there is still much to do to improve targeted MEN2 treatments. New, more potent and selective molecules, or combinatorial strategies may lead to more effective therapies in the near future. Here, we review the rationale for RET targeting in MEN2, the use of currently available drugs and novel preclinical and clinical RET inhibitor candidates.
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Camacho, Cleber P., Ana O. Hoff, Susan C. Lindsey, et al. "Early diagnosis of multiple endocrine neoplasia type 2B: a challenge for physicians." Arquivos Brasileiros de Endocrinologia & Metabologia 52, no. 8 (2008): 1393–98. http://dx.doi.org/10.1590/s0004-27302008000800031.
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BACKGROUND: The hereditary form of medullary thyroid carcinoma may occur isolated as a familial medullary thyroid carcinoma (FMTC) or as part of Multiple Endocrine Neoplasia 2A (MEN2A) and 2B (MEN2B). MEN2B is a rare syndrome, its phenotype may usually, but not always, be noted by the physician. In the infant none of the MEN2B characteristics are present, except by early gastrointestinal dysfunction caused by intestinal neuromas. When available, genetic analysis confirms the diagnosis and guides pre-operative evaluation and extent of surgery. Here we report four cases of MEN2B in which the late diagnosis had a significant impact in clinical evolution and, potentially, in overall survival. CASE REPORT: We report four cases, 2 men and 2 women, with differences in their phenotypes and with a late diagnosis. The first case has a history of severe gastrointestinal obstruction requiring a surgery intervention two days after his birth. The second told had nodules in the oral mucosa and constipation since childhood. The third case referred a history of constipation from birth until 5 months of life. The fourth has had a history of chronic constipation since childhood. DISCUSSION: New concepts have emerged since the RET oncogene was identified in 1993 as the responsible gene for hereditary medullary thyroid carcinoma. The majority of MEN2B individuals have M918T mutation in the exon 16 of RET, with a few cases having a mutation A883F or the association of V804M with E805K, Y806C or S904C mutations. The consensus classifies the RET mutation in codon 918 as of highest risk and recommends total thyroidectomy and central lymph node dissection until 6 months after birth. A fast and precise diagnosis is essential to reach these goals. The identification of early manifestations such as intestinal ganglioneuromatosis and oral mucosal neuromas should prompt the physician to initiate an investigation for multiple endocrine neoplasia type 2B. CONCLUSION: The diagnosis of MEN2B is very important to allow appropriate investigation of associated diseases and to allow counseling and appropriate screening of relatives for a RET mutation. Even patients with MEN2B, which often have typical physical features, may not be properly recognized and be followed as a sporadic case. Based on this, all suspicious cases of multiple endocrine neoplasia should undergo a molecular genetic test.
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Fuller, Sarah, Jaydira Del Rivero, David Venzon, et al. "Pulmonary Function in Patients With Multiple Endocrine Neoplasia 2B." Journal of Clinical Endocrinology & Metabolism 105, no. 9 (2020): 2919–28. http://dx.doi.org/10.1210/clinem/dgaa296.
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Abstract Context Multiple endocrine neoplasia type 2B (MEN2B) is a rare cancer predisposition syndrome resulting from an autosomal-dominant germline mutation of the RET proto-oncogene. No prior studies have investigated pulmonary function in patients with MEN2B. Objective This study characterized the pulmonary function of patients with MEN2B. Design This is a retrospective analysis of pulmonary function tests (PFTs) and chest imaging of patients enrolled in the Natural History Study of Children and Adults with MEN2A or MEN2B at the National Institutes of Health. Results Thirty-six patients with MEN2B (18 males, 18 females) were selected based on the availability of PFTs; 27 patients underwent at least 2 PFTs and imaging studies. Diffusion abnormalities were observed in 94% (33/35) of the patients, with 63% (22/35) having moderate to severe defects. A declining trend in diffusion capacity was seen over time, with an estimated slope of −2.9% per year (P = 0.0001). Restrictive and obstructive abnormalities were observed in 57% (20/35) and 39% (14/36), respectively. Computed tomography imaging revealed pulmonary thin-walled cavities (lung cysts) in 28% (9/32) of patients and metastatic lung disease in 34% (11/32) of patients; patients with metastatic lung lesions also tended to have thin-walled cavities (P = 0.035). Conclusions This study characterized pulmonary function within a MEN2B cohort. Diffusion, restrictive, and obstructive abnormalities were evident, and lung cysts were present in 28% of patients. Further research is required to determine the mechanism of the atypical pulmonary features observed in this cohort.
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Klein, I., O. Esik, V. Homolya, F. Szeri, and A. Varadi. "Molecular genetic diagnostic program of multiple endocrine neoplasia type 2A and familial medullary thyroid carcinoma syndromes in Hungary." Journal of Endocrinology 170, no. 3 (2001): 661–66. http://dx.doi.org/10.1677/joe.0.1700661.
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Medullary thyroid carcinoma (MTC) occurs usually in sporadic form, but about a quarter of the cases are hereditary and appear as part of one of the multiple endocrine neoplasia type 2 (MEN2) syndromes. Mutations in the RET protooncogene are known to be the cause of the MEN2A and familial medullary thyroid carcinoma (FMTC) syndromes in the majority of the families. Direct DNA testing allows prophylactic thyroidectomy to be offered to individuals carrying a mutation in the above codons, and in mutation-negative cases it reduces the yearly screening-related burden on family members at risk of the disease. By DNA sequencing and PCR-restriction fragment length polymorphisms, 65 MTC probands were examined for mutations in residues 609, 611, 618, 620 of exon 10, and in residues 634, 768, 804 of exons 11, 13, and 14 respectively of the RET protooncogene. In our study, mutations in the above codons were detected in all of the 14 clinically MEN2A and FMTC families. One of these mutations, TGC609 TCC has not been reported previously. Of the 14 probands with the mutation, 25 relatives also had the identified mutation and 18 relatives proved to be non-carriers. Among the 51 probands with clinically sporadic MTC, none was found to carry a mutation in the above positions even if indirect signs of MTC, pheochromocytoma or hyperparathyroidism could be detected in some families. The frequency of the TGC634AGC mutation is unexpectedly high in our samples, which can probably be attributed to a founder effect. We conclude that screening for mutations in these codons is effective in families fulfilling the strict clinical criteria of MEN2A or FMTC.
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van den Broek, Medard F. M., Bernadette P. M. van Nesselrooij, Carolina R. C. Pieterman, et al. "Clues For Genetic Anticipation In Multiple Endocrine Neoplasia Type 1." Journal of Clinical Endocrinology & Metabolism 105, no. 7 (2020): e2491-e2500. http://dx.doi.org/10.1210/clinem/dgaa257.
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Abstract Context Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant hereditary disease caused by the loss of function of the MEN1 gene, a tumor-suppressor gene that encodes the protein menin. It is characterized by the occurrence of primary hyperparathyroidism (pHPT), duodenopancreatic neuroendocrine tumors (dpNET), pituitary tumors (PIT), adrenal adenomas, and bronchopulmonary (bp-NET), thymic, and gastric neuroendocrine tumors. More insight into factors influencing the age-related penetrance of MEN1 manifestations could provide clues for more personalized screening programs. Objective To investigate whether genetic anticipation plays a role in the largest known MEN1 families in the Netherlands. Methods All Dutch MEN1 families with ≥ 10 affected members in ≥ 2 successive generations were identified. Age at detection of the different MEN1-related manifestations were compared among generations using regression analyses adjusted for competing risks. To correct for the beneficial effect of being under surveillance, manifestations occurring during surveillance were also separately compared. Results A total of 152 MEN1 patients from 10 families were included. A significantly decreased age at detection of pHPT, dpNET, PIT, and bp-NET was found in successive generations (P &lt; 0.0001). Adjusted analyses led to the same results. Conclusions These results suggest the presence of genetic anticipation. However, due to a risk of residual bias, the results must be interpreted with caution. After independent validation in other cohorts and further translational research investigating the molecular mechanisms explaining this phenomenon in MEN1, the results might add to future, more personalized, screening protocols and earlier screening for future generations of MEN1 patients.
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Pradeep, Pallavi, and Yuval Eisenberg. "A Rare Presentation of Multiple Endocrine Neoplasia Type 1." Journal of the Endocrine Society 5, Supplement_1 (2021): A988—A989. http://dx.doi.org/10.1210/jendso/bvab048.2022.
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Abstract Background: Multiple endocrine neoplasia type 1 (MEN1) is a rare, autosomal dominant inherited syndrome caused by mutations in the MEN1 tumor suppressor gene with a reported incidence of 2 in 100,000. Clinical Case: A 26-year-old Caucasian female was seen for surveillance screening given positive familial mutation in the MEN1 gene. She had a significant family history of pathogenic MEN1 in her son, brother, father and paternal aunt. On presentation, she denied any history of headache, nipple discharge, kidney stones, fractures, heart burn, abdominal pain, diarrhea, hypoglycemia, flushing, lightheadedness. She was on hormonal IUD for contraception and had not had menstrual cycles for the last 6 months. Vital signs and physical examination were unremarkable. Her initial evaluation included a normal calcium of 9.8mg/dL (RR:8.6-10.6mg/dL), PTH of 70pg/ml (RR:12-88pg/ml), 25OH-vitamin-D of 11ng/ml (RR:20-80ng/ml). She had normal gastrin, chromogranin A, glucagon, and vasoactive intestinal peptide levels. Prolactin was 17.6ng/ml (RR:3.3-26.7 ng/ml). MRI pituitary showed a 6mm lesion representing a Rathke’s cleft cyst, not compressing surrounding structures. Two months following the initial encounter, she presented with abdominal pain, nausea, vomiting. She was found to have an obstructing renal stone requiring stent placement. Calcium was 10.1mg/dl. She was also noted to have an incidental pancreatic tail mass of 4.2cm on CT abdomen. She underwent laparoscopic robotic distal spleno-pancreatectomy. Surgical pathology showed a well differentiated 3.5cm neuroendocrine tumor with negative margins, which stained positively for insulin. She had not reported symptoms of weight gain or any episodes suspicious for sympathoadrenal activation or neuroglycopenia, and was again confirmed after surgery. Patient was re-admitted to the hospital for right-sided flank pain and was found to have a new 6mm obstructing calculus with moderate hydronephrosis of the right kidney. Corrected calcium level was found to be mildly elevated at 11.1mg/dL. Repeat PTH was stable at 81pg/ml, and urinary calcium was elevated at 447.3mg/24h (RR:50-250mg/24h). Subsequently, she underwent 3.5 gland parathyroidectomy and thymectomy. On POD20, PTH was 29pg/ml and calcium was 8.6mg/dl. Conclusion: This case highlights a rare presentation of MEN1 with an asymptomatic insulinoma and nephrolithiasis, despite having normal calcium and PTH levels initially. Primary hyperparathyroidism is the most common presentation of MEN1, seen in up to 90% of patients. The second most common finding in MEN1 patients, reported in 70% of the cases, are entero-pancreatic tumors, the most common being gastrinoma. Insulinoma, which is less common and is seen in only 10-30% patients, needs documentation of Whipple’s triad. Interestingly, our patient never had any history of hypoglycemia.
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Walls, Gerard V., Anita A. C. Reed, Jeshmi Jeyabalan, et al. "Proliferation Rates of Multiple Endocrine Neoplasia Type 1 (MEN1)-Associated Tumors." Endocrinology 153, no. 11 (2012): 5167–79. http://dx.doi.org/10.1210/en.2012-1675.
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Abstract Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized by the combined occurrence of parathyroid and adrenocortical tumors, and neuroendocrine tumors (NETs) of the pancreas and pituitary. The pancreatic NETs are predominantly gastrinomas and insulinomas, and the pituitary NETs are mostly prolactinomas and somatotrophinomas. We postulated that the different types of pancreatic and pituitary NETs may be partly due to differences in their proliferation rates, and we therefore assessed these in MEN1-associated tumors and gonadal tumors that developed in mice deleted for an Men1 allele (Men1+/−). To label proliferating cells in vivo, Men1+/− and wild-type (Men1+/+) mice were given 5-bromo-2-deoxyuridine (BrdU) in drinking water from 1–12 wk, and tissue sections were immunostained using anti-BrdU and hormone-specific antibodies. Proliferation in the tumors of Men1+/− mice was significantly (P &lt; 0.001) increased when compared with the corresponding normal Men1+/+ tissues. Pancreatic, pituitary and adrenocortical proliferation fitted first- and second-order regression lines in Men1+/+ tissues and Men1+/− tumors, respectively, R2 = 0.999. Apoptosis was similar in Men1+/− pancreatic, pituitary, and parathyroid tumors when compared with corresponding normal tissues, decreased in Men1+/− adrenocortical tumors, but increased in Men1+/− gonadal tumors. Mathematical modeling of NET growth rates (proliferation minus apoptosis rates) predicted that in Men1+/− mice, only pancreatic β-cells, pituitary lactotrophs and somatotrophs could develop into tumors within a murine lifespan. Thus, our studies demonstrate that Men1+/− tumors have low proliferation rates (&lt;2%), second-order kinetics, and the higher occurrence of insulinomas, prolactinomas, and somatotrophinomas in MEN1 is consistent with a mathematical model for NET proliferation.
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Perren, Aurel, Martin Anlauf, Tobias Henopp, et al. "Multiple Endocrine Neoplasia Type 1 (MEN1): Loss of One MEN1 Allele in Tumors and Monohormonal Endocrine Cell Clusters But Not in Islet Hyperplasia of the Pancreas." Journal of Clinical Endocrinology & Metabolism 92, no. 3 (2007): 1118–28. http://dx.doi.org/10.1210/jc.2006-1944.
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Abstract Context: The occurrence of multiple small pancreatic endocrine tumors in patients suffering from multiple endocrine neoplasia type 1 (MEN1) represents a unique possibility to study early neoplasms and their potential precursor lesions. To date, it is unknown whether small islet-like endocrine cell clusters found in MEN1 patients are neoplastic or rather hyperplastic. It is also unclear whether microadenomas develop from islets. Design: We hypothesized that monohormonal endocrine cell clusters observed in MEN1 patients are small neoplasms with loss of heterozygosity of the MEN1 locus. Using a technique combining fluorescence in situ hybridization of the MEN1 locus and the centromeric region of chromosome 11q with hormone immunostaining, we examined resection specimens from four MEN1 patients. We focused our investigations on the following: 1) typical microadenomas; 2) monohormonal endocrine cell clusters; 3) endocrine and exocrine structures entrapped in microadenomas; and 4) morphologically normal islets. Results: Loss of one MEN1 allele was found in all 27 microadenomas and 19 of 20 (95%) monohormonal endocrine cell clusters. By contrast, it was absent in islets and ductal or acinar structures. Our results indicate that monohormonal endocrine cell clusters represent a minute form of microadenomas. Conclusion: The frequent presence of single nonneoplastic insulin cells in microadenomas and the occurrence of microadenomas in islets suggest an islet origin of microadenomas. Islet hyperplasia does not seem to be an obligatory stage in pancreatic MEN1-associated tumor development.
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Jindřichová, Š, J. Včelák, P. Vlček, M. Neradilová, J. Němec, and B. Bendlová. "Screening of six risk exons of the RET proto-oncogene in families with medullary thyroid carcinoma in the Czech Republic." Journal of Endocrinology 183, no. 2 (2004): 257–65. http://dx.doi.org/10.1677/joe.1.05838.
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Medullary thyroid carcinoma (MTC) occurs as a sporadic form (75%) or as an autosomal dominant inherited familial disorder (25%) called familial MTC (FMTC) or as multiple endocrine neoplasia type 2 (MEN2) syndromes. Germ-line mutations in the rearranged during transfection (RET) proto-oncogene in exons 10, 11, 13, 14, 15 and 16 are known to be a cause of most of the familial forms. In this paper we report molecular genetic testing of 106 families with MTC (358 tested persons) from the Czech Republic in which we directly sequenced these six exons of the RET proto-oncogene. We detected germ-line mutations in 100% of MEN2B families (4/4 families), 90% of MEN2A families (9/10), 40% of FMTC families (4/10) and 7% of apparently sporadic MTC (6/82). Eleven different germ-line mutations were revealed. MEN2B was associated with mutation Met918 Thr in exon 16. In one MEN2B family beside this mutation the Tyr791 Phe was also found, which has not yet been reported. MEN2A was restricted to different mutations in exon 11 (codon 634). In FMTC and ‘sporadic’ MTC families the mutations in exons 10, 11, 13 and 14 were detected. The genotype/phenotype correlations are given. Genetic testing revealed germ-line mutations in 23 index patients, 24 family members and excluded them in 53 relatives.
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Turner, Jeremy J. O., Poloko D. Leotlela, Anna A. J. Pannett, et al. "Frequent Occurrence of an Intron 4 Mutation in Multiple Endocrine Neoplasia Type 1." Journal of Clinical Endocrinology & Metabolism 87, no. 6 (2002): 2688–93. http://dx.doi.org/10.1210/jcem.87.6.8607.
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MEN1 is an autosomal dominant disorder characterized by parathyroid, pituitary, and pancreatic tumors. The MEN1 gene is located on chromosome 11q13 and encodes a 610-amino acid protein. MEN1 mutations are of diverse types and are scattered throughout the coding region, such that almost every MEN1 family will have its individual mutation. To further characterize such mutations we ascertained 34 unrelated MEN1 probands and undertook DNA sequence analysis. This identified 17 different mutations in 24 probands (2 nonsense, 2 missense, 2 in-frame deletions, 5 frameshift deletions, 1 frameshift deletional-insertion, 3 frameshift insertions, 1 donor splice site mutation, and a g→a transition that resulted in a novel acceptor splice site in intron 4). The intron 4 mutation was found in 7 unrelated families, and the tumors in these families varied considerably, indicating a lack of genotype-phenotype correlation. However, this intron 4 mutation is the most frequently occurring germline MEN1 mutation (∼10% of all mutations), and together with 5 others at codons 83–84, 118–119, 209–211, 418, and 516, accounts for 36.6% of all mutations, a finding that indicates an approach for identifying the widely diverse MEN1 mutations.
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Maciel, Rui M. B., Cleber P. Camacho, Lígia V. M. Assumpção, et al. "Genotype and phenotype landscape of MEN2 in 554 medullary thyroid cancer patients: the BrasMEN study." Endocrine Connections 8, no. 3 (2019): 289–98. http://dx.doi.org/10.1530/ec-18-0506.
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Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant genetic disease caused by RET gene germline mutations that is characterized by medullary thyroid carcinoma (MTC) associated with other endocrine tumors. Several reports have demonstrated that the RET mutation profile may vary according to the geographical area. In this study, we collected clinical and molecular data from 554 patients with surgically confirmed MTC from 176 families with MEN2 in 18 different Brazilian centers to compare the type and prevalence of RET mutations with those from other countries. The most frequent mutations, classified by the number of families affected, occur in codon 634, exon 11 (76 families), followed by codon 918, exon 16 (34 families: 26 with M918T and 8 with M918V) and codon 804, exon 14 (22 families: 15 with V804M and 7 with V804L). When compared with other major published series from Europe, there are several similarities and some differences. While the mutations in codons C618, C620, C630, E768 and S891 present a similar prevalence, some mutations have a lower prevalence in Brazil, and others are found mainly in Brazil (G533C and M918V). These results reflect the singular proportion of European, Amerindian and African ancestries in the Brazilian mosaic genome.
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Margraf, R. L., J. D. Durtschi, J. E. Stephens, M. Perez, and K. V. Voelkerding. "Determination ofRETSequence Variation in an MEN2 Unaffected Cohort Using Multiple-Sample Pooling and Next-Generation Sequencing." Journal of Thyroid Research 2012 (2012): 1–9. http://dx.doi.org/10.1155/2012/318232.
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Multisample, nonindexed pooling combined with next-generation sequencing (NGS) was used to discoverRETproto-oncogene sequence variation within a cohort known to be unaffected by multiple endocrine neoplasia type 2 (MEN2). DNA samples (113 Caucasians, 23 persons of other ethnicities) were amplified forRETintron 9 to intron 16 and then divided into 5 pools of <30 samples each before library prep and NGS. Two controls were included in this study, a single sample and a pool of 50 samples that had been previously sequenced by the same NGS methods. All 59 variants previously detected in the 50-pool control were present. Of the 61 variants detected in the unaffected cohort, 20 variants were novel changes. Several variants were validated by high-resolution melting analysis and Sanger sequencing, and their allelic frequencies correlated well with those determined by NGS. The results from this unaffected cohort will be added to theRETMEN2 database.
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Scholten, Anouk, Menno R. Vriens, Geert Jan E. Cromheecke, Inne H. M. Borel Rinkes, and Gerlof D. Valk. "Hemodynamic instability during resection of pheochromocytoma in MEN versus non-MEN patients." European Journal of Endocrinology 165, no. 1 (2011): 91–96. http://dx.doi.org/10.1530/eje-11-0148.
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ObjectiveHemodynamic (HD) instability still underlies difficulties during pheochromocytoma resection. Little is known about HD instability in patients with multiple endocrine neoplasia (MEN) type 2-related pheochromocytoma. Our aim was to assess differences in HD during pheochromocytoma resection between MEN2 and non-MEN patients. In addition, we sought to identify risk factors for intraoperative HD instability.DesignRetrospective cohort study.MethodsA total of 22 MEN2 and 34 non-MEN patients underwent 61 pheochromocytoma resections at the University Medical Center Utrecht between 2000 and 2010. All MEN2-related pheochromocytomas were diagnosed by annual screening. HD instability was assessed by measuring the frequency of hypotensive (mean arterial blood pressure (MABP) <60 mmHg) and/or hypertensive (systolic arterial blood pressure (SABP) >200 mmHg) episodes.ResultsCompared with non-MEN patients, MEN2 patients were younger at diagnosis, had less symptoms, lower hormone levels, and smaller tumors. Intraoperatively, MEN2 patients had a similar frequency of hypertensive episodes (1.3 vs 1.9, P=0.162, 95% confidence interval (CI): −6.7 to 35.4) and a similar maximum SABP (200 vs 220 mmHg, P=0.180, 95% CI: −9.7 to 50.5). However, MEN2 patients experienced less frequent (1.04 vs 2.6, P=0.003, 95% CI: 0.57 to 2.6) and less severe hypotensive episodes after tumor resection (lowest MABP: 52.5 vs 45.6 mmHg, P=0.015, 95% CI: −12.6 to 1.16). Tumor size was an independent risk factor for HD instability for the total group after multivariate analysis.ConclusionMEN2 patients with pheochromocytoma, despite their smaller tumors, do not distinguish themselves from non-MEN patients in terms of hypertensive episodes during pheochromocytoma resection. Therefore, pretreatment with α- and β-blockade remains the standard of care in MEN2-related as well as in non-MEN-related pheochromocytomas.
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Yang, Joung Wook, Su Kyoung Kwon, Jeong Hoon Kim, Young Sik Choi, and Yo-Han Park. "Concurrent Type 2 Diabetes and Multiple Endocrine Neoplasia Type 1 With a Novel MEN1 Gene Mutation." Journal of Medical Cases 5, no. 11 (2014): 596–600. http://dx.doi.org/10.14740/jmc1973w.
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Khalifa, Maram, Hassaan Aftab, and Vitaly Kantorovich. "Metastatic Thyroid Cancer After Thyroidectomy in Patient With Neuroendocrinal Tumor." Journal of the Endocrine Society 5, Supplement_1 (2021): A1000—A1001. http://dx.doi.org/10.1210/jendso/bvab048.2047.
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Abstract Background: Multiple endocrine neoplasia type 2 is an autosomal dominant disorder with an estimated prevalence of 1 per 30,000 in the general population. Classical multiple endocrine neoplasia 2A is the most common variant. It is a heritable predisposition to medullary thyroid cancer, pheochromocytoma, and primary parathyroid hyperplasia. The respective frequency of these tumors in classical MEN2A is over 90 percent for MTC, approximately 10 to 50 percent for pheochromocytoma, and 10 to 20 percent for multigland parathyroid hyperplasia. Discussion: our interesting patient is a 67-year-old patient with past medical history of prophylactic total thyroidectomy at the age of 25 years after a positive pentagastrin test (sister was diagnosed with MTC, pheochromocytoma),niece with metastatic kidney cancer.at that time, patient had benign pathology. Patient presented to the ED with a complain of shortness of breath after being referred by her PCP for evaluation of possible pneumonia. In the ED, her vitals were within normal, chest X-ray was done and didn’t show pneumonia but the patient was found to have elevated procalcitonin of 22.7 ng/mL(0.09 ng/mL) CT chest was done and showed enlarged necrotic cervical lymphadenopathy which was confirmed by obtaining CT of the neck. Patient had right cervical LN core biopsy, pathology was positive for medullary thyroid cancer with Immunohistochemical studies positive for TTF-1, chromogranin, synaptophysin and calcitonin, testing for pheochromocytoma came back within normal, CEA 70.7ng/ml (&lt;0.25 ng/ml), calcitonin 2949 pg/ml (5 pg/mL) Chromogranin was high at 453 ng/ml (25 - 140 ng/mL) had PET CT with multiple low right cervical and supraclavicular lymph nodes with internal calcifications and abnormal FDG activity, which were suspicious for medullary thyroid cancer metastases, she eventually had radical neck dissection with pathology from inferior parathyroid gland positive for medullary thyroid cancer and 12/15 regional LN positive for malignancy, after the procedure her calcitonin dropped nicely to 194pg/ml, CEA dropped to 4.0, chromogrannin to 394, she was referred to genetic testing and tested positive for pathogenic variant within RET (c.1859G&gt;T, p.Cys620Phe), which is known to be associated with multiple endocrine neoplasia type 2A, she is currently being evaluated for Lutathera treatment. Conclusion: In contrast to MEN1, in which the long-term benefit of early diagnosis by genetic screening is not well established, early diagnosis by screening of “at-risk” family members in MEN2 with positive RET mutation kindreds is essential because MTC is a life-threatening disease that can be cured or prevented by early thyroidectomy. Total thyroidectomy has been recommended for patients as young as 3 years for MEN2A if they contain the genetic mutation.
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Wells, Samuel A. "Advances in the management of MEN2: from improved surgical and medical treatment to novel kinase inhibitors." Endocrine-Related Cancer 25, no. 2 (2018): T1—T13. http://dx.doi.org/10.1530/erc-17-0325.
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Medullary thyroid carcinoma (MTC), a tumor derived from the neural crest, occurs either sporadically or as the dominant component of the type 2 multiple endocrine neoplasia (MEN) syndromes, MEN2A and MEN2B. The discovery that mutations in the RET protooncogene cause hereditary MTC was of great importance, since it led to the development of novel methods of diagnosis and treatment. For example, the detection of a mutated RET allele in family members at risk for inheriting MEN2A or MEN2B signaled that they would develop MTC, and possibly other components of the syndromes. Furthermore, the detection of a mutated allele created the opportunity, especially in young children, to remove the thyroid before MTC developed, or while it was confined to the gland. The discovery also led to the development of molecular targeted therapeutics (MTTs), mainly tyrosine kinase inhibitors, which were effective in the treatment of patients with locally advanced or metastatic MTC. While responses to MTTs are often dramatic, they are highly variable, and almost always transient, because the tumor cells become resistant to the drugs. Clinical investigators and the pharmaceutical industry are focusing on the development of the next generation of MTTs, which have minimal toxicity and greater specificity for mutated RET.
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Wang, Bao-Ping, Wei-Jun Tian, Jie Zhang, Chang-Xin Jiang, Hui-Qi Qu, and Mei Zhu. "Nonfunctional pancreatic endocrine tumor in the peripancreatic region in a Chinese patient with multiple endocrine neoplasia type 1." Journal of International Medical Research 46, no. 2 (2017): 908–15. http://dx.doi.org/10.1177/0300060517728653.
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Nonfunctional pancreatic neuroendocrine tumors (NF-pNETs) in patients with multiple endocrine neoplasia type 1 (MEN1), which results from a mutation in the MEN1 gene, are commonly small, multiple tumors located in the pancreatic head and inside the pancreatic parenchyma. We herein describe a 35-year-old woman with bone pain and a 7-year history of a prolactinoma. She was clinically diagnosed with MEN1 based on the presence of the prolactinoma and parathyroid hyperplasia. Abdominal computed tomography revealed a 5-cm mass close to the splenic hilum. This soft tissue tumor, which was located outside the pancreatic parenchyma and the tissue origin of which could not be identified preoperatively, was found to be connected to the pancreatic tail. After resection, histological examination revealed a well-differentiated neuroendocrine tumor of pancreatic origin. Genetic testing revealed a heterozygous transition mutation of guanine to adenine at the coding nucleotide 133 in exon 2 (c.133G>A), resulting in an amino acid substitution of glutamic acid with lysine (E45K) in the MEN1 gene. This patient with MEN1 presented with a clinical condition involving a single non-metastatic NF-pNET located outside the pancreatic parenchyma with a missense mutation in the MEN1 gene, which could easily have been misdiagnosed as an accessory spleen.
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Wang, Yong, and Hui Zhang. "Multiple endocrine neoplasia type 1 with refractory hypoglycemia and lung and liver metastases: a case report." Journal of International Medical Research 49, no. 1 (2021): 030006052096168. http://dx.doi.org/10.1177/0300060520961682.
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Background Multiple endocrine neoplasia type 1 (MEN1) is a rare autosomal dominant genetic disease. MEN1 with multiple endocrine adenomatosis complicated by multiple endocrine tumors is often misdiagnosed or missed. Herein, we describe the first reported case of refractory hypoglycemia and liver and lung metastases in a patient with MEN1. Case presentation: A 40-year-old man presented with a 3-month history of intermittent palpitations, fatigue, and sweating. The patient had a history of prolactinoma resection and refractory hypoglycemia 2 years earlier. Analyses of blood samples showed a decrease in random and fasting blood glucose and an increase in prolactin (PRL). Computed tomography (CT) and magnetic resonance imaging scans revealed two substantial masses in the pancreas and large masses in the liver and lung. Positron emission tomography-CT images showed hypermetabolic masses in the pancreatic body and tail. The liver and lung lesions were also hypermetabolic. The pancreatic lesion was surgically removed, and pathology confirmed that the mass was MEN1. The liver and lung masses were confirmed as metastatic tumors. Conclusion If clinicians better understand MEN1, they can obtain a detailed patient and family history during the initial visit, allowing earlier diagnosis and intervention and improved prognosis.
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Coțofană, Ioana, Roxana Roșca, Alexandra Mirică, et al. "CLINICAL AND SURGICAL ATTITUDE IN A MEN2 SYNDROME CASE WITH MEDULLARY THYROID CARCINOMA RECURRENCE DURING PREGNANCY." Journal of Surgical Sciences 2, no. 4 (2015): 189–92. http://dx.doi.org/10.33695/jss.v2i4.134.
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Multiple endocrine neoplasia type 2 is a group of medical disorders associated with tumours of the endocrine system. The tumours may be benign or malignant. They generally occur in the endocrine organs (e.g. thyroid, parathyroid, and adrenals), but may also occur in the endocrine tissues of organs not classically thought of as endocrine. We present the case of a 28-year-old female, with history of MEN2A syndrome confirmed by genetic screening and manifested by bilateral pheochromocytoma, for which she underwent right adrenalectomy in 2009 and left adrenalectomy in 2011, as well as by medullary carcinoma of the thyroid, for which total thyroidectomy was performed in 2009. At present, the patient is under replacement treatment of the thyroid function with LT4 and glucocorticoid and mineralocorticoid replacement therapy with Prednisone and Astonin. Currently, the patient has been periodically presenting herself for clinical and therapeutic endocrinological re-evaluation, in the context of an ongoing pregnancy. During a presentation, in September 2015, the pregnancy being in its 24th week, at ultrasonography, a possible remnant of thyroid tissue was detected, a superior and mediolateral adenopathy, well defined, with some interior calcifications, discretely vascularized, therefore of a suspicious nature and a left supraclavicular small cluster of microcalcifications was also detected. Calcitonin blood level was measured in order to dynamically correlate its evolution with the new ultrasound findings with a significant increase at the current dosing reaching 587.20 pg / ml.
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Damjanovic, Svetozar S., Jadranka A. Antic, Valentina I. Elezovic-Kovacevic, et al. "ARMC5 Alterations in Patients With Sporadic Neuroendocrine Tumors and Multiple Endocrine Neoplasia Type 1 (MEN1)." Journal of Clinical Endocrinology & Metabolism 105, no. 12 (2020): e4531-e4542. http://dx.doi.org/10.1210/clinem/dgaa631.
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Abstract Context Adrenal lesions are frequent among patients with sporadic neuroendocrine tumors (spNETs) or multiple endocrine neoplasia type 1 (MEN1). Armadillo repeat-containing 5 (ARMC5)-inactivating variants cause adrenal tumors and possibly other neoplasms. Objective The objective of this work is to investigate a large cohort spNETs or MEN1 patients for changes in the ARMC5 gene. Patients and Methods A total of 111 patients, 94 with spNET and 17 with MEN1, were screened for ARMC5 germline alterations. Thirty-six tumors (18 spNETs and 18 MEN1 related) were collected from 20 patients. Blood and tumor DNA samples were genotyped using Sanger sequencing and microsatellite markers for chromosomes. ARMC5 and MEN1 expression were assessed by immunohistochemistry. Results In 76 of 111 (68.4%) patients, we identified 16 different ARMC5 germline variants, 2 predicted as damaging. There were no differences in the prevalence of ARMC5 variants depending on the presence of MEN1-related adrenal lesions. Loss of heterozygosity (LOH) at chromosome 16p and ARMC5 germline variants were present together in 23 or 34 (67.6%) tumors; in 7 of 23 (30.4%) their presence led to biallelic inactivation of the ARMC5 gene. The latter was more prevalent in MEN1-related tumors than in spNETs (88.9% vs 38.9%; P = .005). LOH at the chromosome 16p (ARMC5) and 11q (MEN1) loci coexisted in 16/18 MEN1-related tumors, which also expressed lower ARMC5 (P = .02) and MEN1 (P = .01) proteins compared to peritumorous tissues. Conclusion Germline ARMC5 variants are common among spNET and MEN1 patients. ARMC5 haploinsufficiency or biallelic inactivation in spNETs and MEN1-related tumors suggests that ARMC5 may have a role in modifying the phenotype of patients with spNETs and/or MEN1 beyond its known role in macronodular adrenocortical hyperplasia.
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van den Broek, Medard F. M., Ester B. G. Rijks, Peter G. J. Nikkels, et al. "Timely diagnosis of multiple endocrine neoplasia 2B by identification of intestinal ganglioneuromatosis: a case series." Endocrine 72, no. 3 (2021): 905–14. http://dx.doi.org/10.1007/s12020-021-02607-2.
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Abstract Background Medullary thyroid carcinoma (MTC) in childhood is rare and has an unfavorable prognosis. To improve outcome, early diagnosis is essential. In patients with multiple endocrine neoplasia type 2B (MEN2B), MTC can occur already before the age of 1 year. Recognition of non-endocrine features of MEN2B may lead to timely diagnosis. Purpose To describe how early recognition of non-endocrine features can lead to a timely diagnosis of MEN2B as well as the effect of recognition of premonitory symptoms on prognosis. Methods A retrospective case series from the University Medical Center Utrecht/Wilhelmina Children’s Hospital, a Dutch national expertise center for MEN patients. All eight MEN2B patients in follow-up between 1976 and 2020 were included and medical records reviewed. Results Intestinal ganglioneuromatosis (IGN) as the cause of gastrointestinal (GI) symptoms was detected in seven patients. In three of them within months after birth. This led to early diagnosis of MEN2B, which allowed subsequent curative thyroid surgery. On the contrary, a MEN2B diagnosis later in childhood—in three patients (also) triggered by oral neuromas/neurofibromas—led to recurrent, persistent, and/or progressive MTC in five patients. Conclusions Neonatal GI manifestations offer the most important window of opportunity for early detection of MEN2B. By accurate evaluation of rectal biopsies in patients with early onset severe constipation, IGN can be timely detected, while ruling out Hirschsprung’s disease. MEN2B gene analysis should follow detection of IGN and—when confirmed—should prompt possibly still curative thyroid surgery.
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Margraf, Rebecca L., Rong Mao, W. Edward Highsmith, Leonard M. Holtegaard, and Carl T. Wittwer. "Mutation Scanning of the RET Protooncogene Using High-Resolution Melting Analysis." Clinical Chemistry 52, no. 1 (2006): 138–41. http://dx.doi.org/10.1373/clinchem.2005.052951.
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Abstract Background: Single-base pair missense mutations in exons 10, 11, 13, 14, 15, and 16 of the RET protooncogene are associated with the autosomal dominant multiple endocrine neoplasia type 2 (MEN2) syndromes: MEN2A, MEN2B, and familial medullary thyroid carcinoma. The current widely used approach for RET mutation detection is sequencing of the exons. Methods: Because RET mutations are rare and the majority are heterozygous mutations, we investigated RET mutation detection by high-resolution amplicon melting analysis. This mutation scanning technique uses a saturating double-stranded nucleic acid binding dye, LCGreen®, and the high-resolution melter, HR-1™, to detect heterozygous and homozygous sequence variations. Mutant genotypes are distinguished from the wild-type genotype by an altered amplicon melting curve shape or position. Results: Samples of 26 unique RET mutations, 4 nonpathogenic polymorphisms, or the wild-type genotype were available for this study. The developed RET mutation-scanning assay differentiated RET sequence variations from the wild-type genotype by altered derivative melting curve shape or position. A blinded study of 80 samples (derived from the 35 mutant, polymorphism, or wild-type samples) demonstrated that 100% of RET sequence variations were differentiated from wild-type samples. For exons 11 and 13, the nonpathogenic polymorphisms could be distinguished from the pathogenic RET mutations. Some RET mutations could be directly genotyped by the mutation scanning assay because of unique derivative melting curve shapes. Conclusion: RET high-resolution amplicon melting analysis is a sensitive, closed-tube assay that can detect RET protooncogene sequence variations.
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van Nederveen, Francien H., Esther Korpershoek, Ronald J. deLeeuw, et al. "Array-comparative genomic hybridization in sporadic benign pheochromocytomas." Endocrine-Related Cancer 16, no. 2 (2009): 505–13. http://dx.doi.org/10.1677/erc-08-0241.
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Pheochromocytomas (PCC) are catecholamine-producing tumors arising from the adrenal medulla that occur either sporadically or in the context of hereditary cancer syndromes, such as multiple endocrine neoplasia type 2 (MEN2), von Hippel-Lindau disease (VHL), neurofibromatosis type 1, and the PCC-paraganglioma syndrome. Conventional comparative genomic hybridization studies have shown loss of 1p and 3q in the majority of sporadic and MEN2-related PCC, and 3p and 11p loss in VHL-related PCC. The development of a submegabase tiling resolution array enabled us to perform a genome-wide high-resolution analysis of 36 sporadic benign PCC. The results show that there are two distinct patterns of abnormalities in these sporadic PCC, one consisting of loss of 1p with or without concomitant 3q loss in 20/36 cases (56%), the other characterized by loss of 3p with or without concomitant 11p loss in 11/36 (31%). In addition, we found loss of chromosome 22q at high frequency (35%), as well as the novel finding of high frequency chromosome 21q loss (21%). We conclude that there appear to be two subgroups of benign sporadic PCC, one of which has a pattern of chromosomal abnormalities that is comparable with PCC from patients with MEN2 and the other that is comparable with the PCC that arise in patients with VHL disease. In addition, genes on 21q and 22q might play a more important role in PCC pathogenesis than had been assumed thus far.
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Vierimaa, O., T. M. L. Ebeling, S. Kytölä, et al. "Multiple endocrine neoplasia type 1 in Northern Finland; clinical features and genotype–phenotype correlation." European Journal of Endocrinology 157, no. 3 (2007): 285–94. http://dx.doi.org/10.1530/eje-07-0195.
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Objective: The existence of genotype–phenotype correlation in multiple endocrine neoplasia type 1 (MEN1) is controversial. Two founder mutations of the MEN1 gene in Northern Finland gave us an opportunity to compare clinical features among heterozygotes of different mutations. Design and methods: Study cohort included 82 MEN1 heterozygotes who were tested for MEN1 during the years 1982–2001. Medical records were reviewed for manifestations of MEN1, other tumours and cause of death by the end of August 2003. Logistic regression analysis was used in evaluating the impact of age, gender and mutational status of affected heterozygotes on the likelihood of developing manifestations of MEN1. Results: Founder mutations 1466del12 and 1657insC were found in 39 and 29 individuals, and D418N, G156R and R527X mutations in 9, 3 and 2 individuals respectively. Except for pituitary adenoma and nonfunctional pancreatic tumour (NFPT), age was a risk factor for all the disease manifestations. For NFPT, frameshift/nonsense mutations (1657insC, R527X) gave an odds ratio (OR) of 3.26 (95% confidence intervals (CI), 1.27–8.33; P = 0.014) compared with in-frame/missense mutations (1466del12, D418N, G156R); including the founder mutation carriers (n = 68) only, the 1657insC mutation gave an OR of 3.56 (CI, 1.29–9.83; P = 0.015). For gastrinoma, in-frame/missense mutations predicted the risk with an OR of 6.77 (CI, 1.31–35.0; P = 0.022), and in the founder mutations group the 1466del12 mutation gave an OR of 15.09 (CI, 1.73–131.9, P = 0.014). Conclusions: In this study population, NFPT was more common in the frameshift/nonsense or 1657insC mutation carriers, whereas gastrinoma was more common in the in-frame/missense or 1466del12 mutation carriers.
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Siqueira, Débora Rodrigues, Lucieli Ceolin, Carla Vaz Ferreira, et al. "Role of RET genetic variants in MEN2-associated pheochromocytoma." European Journal of Endocrinology 170, no. 6 (2014): 821–28. http://dx.doi.org/10.1530/eje-14-0084.
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Background: RET polymorphisms have been involved in the clinical presentation and prognosis of multiple endocrine neoplasia type 2 (MEN2)-associated medullary thyroid carcinoma.ObjectiveTo investigate the effect of RET variants on the penetrance of pheochromocytoma (PHEO) in MEN2 patients. Methods: The RET variants L769L, S836S, and G691S/S904S were evaluated in a cohort of 153 MEN2 patients attending a tertiary teaching hospital. A comparison of RET variant frequencies between patients with and without PHEO was performed. Kaplan–Meier curves and Cox regression analysis were used to estimate the effect of RET variants on the age-dependent penetrance.ResultsA total of 48 (31.4%) patients presented with MEN2-associated PHEOs. The mean age at diagnosis was 35.5±13.4 years, 60.4% of patients were women, and 92.8% had RET mutations at codon 634. The frequencies of RET polymorphisms were as follows: 20.1% L769L, 4.75% S836S, and 17.3% S904S/G691S. We did not observe any association between the frequencies of L769L, S836S, or S904S/G691S variants and PHEO development (all P>0.05). However, individuals carrying two RET polymorphic alleles had an increased estimated risk of PHEO (2.63; 95% CI, 1.4–5.0; P=0.004) and were younger at diagnosis when compared with those with one or no polymorphism (29.6±6.3 and 39.3±14.4 years respectively; P=0.006). Accordingly, additional analysis using Cox proportional hazard models demonstrated that the presence of two RET variants was associated with an increased risk for early PHEO development (hazard ratio, 5.99 (95% CI, 2.24–16.03); P<0.001).ConclusionsRET polymorphic alleles have an additive effect on the estimated risk of age-related PHEO penetrance in MEN2 patients.
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Latteyer, S., L. Klein-Hitpass, C. Khandanpour, et al. "A 6-Base Pair in Frame Germline Deletion in Exon 7 Of RET Leads to Increased RET Phosphorylation, ERK Activation, and MEN2A." Journal of Clinical Endocrinology & Metabolism 101, no. 3 (2016): 1016–22. http://dx.doi.org/10.1210/jc.2015-2948.
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Abstract Context: Multiple endocrine neoplasia type 2 (MEN2) is usually caused by missense mutations in the proto-oncogene, RET. Objective: This study aimed to determine the mutation underlying MEN2A in a female patient diagnosed with bilateral pheochromocytoma at age 31 years and with medullary thyroid carcinoma (MTC) 6 years later. Methods: Leukocyte DNA was used for exome and Sanger sequencing. Wild-type (WT) RET and mutants were expressed in HEK293 cells. Activation of MAPK/ERK and PI3K/AKT was analyzed by Western blotting and luciferase assay. The effect of RET mutants on cell proliferation was tested in a colony forming assay. Results: Exome sequencing revealed a 6-nucleotide/2-amino acid in-frame deletion in exon 7 of RET (c.1512_1517delGGAGGG, p.505_506del). In vitro expression showed that phosphorylation of the crucial tyrosine 905 was much stronger in the p.505_506del RET mutant compared with WT RET, indicating ligand-independent autophosphorylation. Furthermore, the p.505_506del RET mutant induced a strong activation of the MAPK/ERK pathway and the PI3K/AKT pathway. Consequently, the p.505_506del RET mutant cells increased HEK293 colony formation 4-fold compared with WT RET. Conclusion: The finding of bilateral pheochromocytoma and MTC in our patient was highly suspicious of a RET mutation. Exome sequencing revealed a 6-base-pair deletion in exon 7 of RET, an exon not yet associated with MEN2. Increased ligand-independent phosphorylation of the p.505_506del RET mutant, increased activation of downstream pathways, and stimulation of cell proliferation demonstrated the pathogenic nature of the mutation. We therefore recommend screening the whole sequence of RET in MTC and pheochromocytoma patients with red flags for a genetic cause.
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Harding, Brian, Manuel C. Lemos, Anita A. C. Reed, et al. "Multiple endocrine neoplasia type 1 knockout mice develop parathyroid, pancreatic, pituitary and adrenal tumours with hypercalcaemia, hypophosphataemia and hypercorticosteronaemia." Endocrine-Related Cancer 16, no. 4 (2009): 1313–27. http://dx.doi.org/10.1677/erc-09-0082.
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Multiple endocrine neoplasia type 1 (MEN1) is an autosomal dominant disorder characterized in man by parathyroid, pancreatic, pituitary and adrenal tumours. The MEN1 gene encodes a 610-amino acid protein (menin) which is a tumour suppressor. To investigate the in vivo role of menin, we developed a mouse model, by deleting Men1 exons 1 and 2 and investigated this for MEN1-associated tumours and serum abnormalities. Men1+/− mice were viable and fertile, and 220 Men1+/− and 94 Men1+/+ mice were studied between the ages of 3 and 21 months. Survival in Men1+/− mice was significantly lower than in Men1+/+ mice (<68% vs >85%, P<0.01). Men1+/− mice developed, by 9 months of age, parathyroid hyperplasia, pancreatic tumours which were mostly insulinomas, by 12 months of age, pituitary tumours which were mostly prolactinomas, and by 15 months parathyroid adenomas and adrenal cortical tumours. Loss of heterozygosity and menin expression was demonstrated in the tumours, consistent with a tumour suppressor role for the Men1 gene. Men1+/− mice with parathyroid neoplasms were hypercalcaemic and hypophosphataemic, with inappropriately normal serum parathyroid hormone concentrations. Pancreatic and pituitary tumours expressed chromogranin A (CgA), somatostatin receptor type 2 and vascular endothelial growth factor-A. Serum CgA concentrations in Men1+/− mice were not elevated. Adrenocortical tumours, which immunostained for 3-β-hydroxysteroid dehydrogenase, developed in seven Men1+/− mice, but resulted in hypercorticosteronaemia in one out of the four mice that were investigated. Thus, these Men1+/− mice are representative of MEN1 in man, and will help in investigating molecular mechanisms and treatments for endocrine tumours.