Academic literature on the topic 'Mixed phenotype acute leukemia (MPAL)'

Abstract Mixed-phenotype acute leukemia (MPAL) encompasses a heterogeneous group of rare leukemias in which assigning a single lineage of origin is not possible. A variety of different terms and classification systems have been used historically to describe this entity. MPAL is currently defined by a limited set of lineage-specific markers proposed in the 2008 World Health Organization monograph on classification of tumors of hematopoietic and lymphoid tissues. In adult patients, MPAL is characterized by relative therapeutic resistance that may be attributed in part to the high proportion of patients with adverse cytogenetic abnormalities. No prospective, controlled trials exist to guide therapy. The limited available data suggest that an “acute lymphoblastic leukemia–like” regimen followed by allogeneic stem-cell transplant may be advisable; addition of a tyrosine kinase inhibitor in patients with t(9;22) translocation is recommended. The role of immunophenotypic and genetic markers in guiding chemotherapy choice and postremission strategy, as well as the utility of targeted therapies in non–Ph-positive MPALs is unknown.

Leukemia cutis (LC) is defined as infiltration of the skin by leukemic cells resulting in clinically recognizable cutaneous lesions. It is common in congenital leukemia and acute myeloid leukemia. However, LC has rarely been reported with mixed phenotypic acute leukemia (MPAL). We report the case of a lady who presented with erythematous papular and nodular lesions all over the body. Skin biopsy showed leukemic infiltration and bone marrow aspiration showed MPAL of the T/myeloid with monocytic differentiation lineage. This is the first report of an adult patient with MPAL of the T/myeloid with monocytic differentiation type presenting with leukemia cutis. She was started on chemotherapy with Hyper-CVAD. There is complete resolution of the skin lesions and she has achieved bone marrow remission after the first cycle of chemotherapy.

Mixed-phenotype acute leukemia (MPAL) is a heterogeneous category in the World Health Organization classification that comprises acute leukemias with discrete admixed populations of myeloid and lymphoid blasts (“bilineal”) or with extensive coexpression of lymphoid and myeloid markers in a single blast population (“biphenotypic”). Flow cytometric findings suggestive of MPAL are often met with consternation by pathologists and oncologists alike, owing to unfamiliarity with the disease and uncertainty about how MPAL fits into established paradigms for treatment of acute leukemia. The purpose of this review is to explain the diagnostic criteria for MPAL, summarize its biological and clinical features, and address common diagnostic pitfalls of these unusual leukemias.

Abstract Abstract 4811 Background: Mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia with a poor clinical outcome, defined by the blasts express antigens of more than one lineage. MPAL was also named as mixed lineage leukemia, bilineal leukemia, biphenotype leukemia historically. The properly diagnosis of MPAL is crucial for the treatment. The scoring system proposed by European Group for Immunological Characterization of Leukemia (EGIL) in 1995 was the first standard criteria to diagnose MPAL. In 2008, WHO proposed a new scoring criteria to define MPAL. But both of these two systems have their limitation. Methods: We retrospectively analyzed 41 pediatric patients with mixed phenotype acute leukemia from 2000 to 2010 according to EGIL scoring system. All the 41 patients were reclassified according the 2008 WHO classification. Diagnosis, cytogenetics, immunophenotype, treatment and prognosis were analyzed. Results: There were 25 male and 16 female with the mean age of 8 years old. According to EGIL scoring system, the phenotype included T/myeloid (n=16), B/myeloid (n=13), T/B(n=11) and T/B/AML(n=1), respectively. Among the patients, there were 4 MPAL with t(9;22)(q34;q11), 5 with t(12;21)(p13;q22), 1 with inv(16)(p13;q22) and 1 with t(9;9). The overall complete remission (CR) rate was 47% treated by ALL regimen (n=19) and 17% by the AML+ALL combined therapy (n=6). MPAL with t(9;22)(q34;q11) showed poor response (4/4). MPAL with t(12;21)(p13;q22) had a good response to the treatment(4/5). Based on the 2008 WHO criteria, 24 of the 41 MPAL patients were reclassified as MPAL, including T/myeloid type(n=11), B/myeloid type(n=6), T/B(n=7). Three MPAL patients with t(12;21)(p13;q22) diagnosed by EGIL system were excluded by 2008 WHO criteria. Conclusion: Our results suggest that MPAL is a poor outcome disease requiring more accurate classification based on genetic and gene classification. MPAL with t(9;22)(q34;q11) is a predictor of poor outcome. MPAL with t(12;21)(p13;q22) could be treated only by ALL regimen. MPAL with both lymphoid and myeloid markers appears to achieve a better CR rate if treated by ALL regimens alone than treated by ALL+AML combined regimens. Further studies are needed to determine a standard diagnosis and treatment approach for MAPL. Disclosures: Zheng: Beijing Health System High-level Technical Personel Plan: Research Funding.

Mixed-phenotype acute leukemias (MPAL) are rare in children and often lack consensus on optimal management. This review examines the current controversies and emerging paradigms in the management of pediatric MPAL. We examine risk stratification, outcomes of recent retrospective and prospective collaborative trials, and the role of transplantation and precision genomics, and outline emerging targets and concepts in this rare entity.

Abstract Background: Mixed phenotype acute leukemia (MPAL) is a high risk leukemia with features of acute myeloid (AML) and acute lymphoblastic leukemia (ALL), either due to co-expression of antigens of multiple lineages, or the presence of multiple immunophenotypically distinct populations. WHO 2008 classifies MPAL as T/myeloid (T/M), B/myeloid (B/M), MLL rearranged (MLL) MPAL, BCR-ABL1 (Ph+) MPAL, and MPAL not otherwise specified (NOS). Patients are managed with divergent chemotherapeutic approaches with survival estimates of 50-70%. Apart from Ph+ and MLL rearrangement, the genetic basis of MPAL is poorly defined. Our goal was to define the molecular basis of MPAL, and to compare with potentially related forms of leukemia (AML, T-ALL and early T-cell precursor (ETP) ALL) as a rational foundation for future trials. Furthermore, we examined whether multi-lineal cases harbor genetically distinct subclones, or arise from the acquisition of founding alterations in a multi-lineage hematopoietic progenitor. Methods: 155 cases of pediatric leukemia initially diagnosed as MPAL were studied by central pathology review and/or central flow cytometry (134 cases), confirming the diagnosis according to WHO criteria in 115 cases (fig. 1). Median age was 7 years (0-18) with 52 T/M, 37 B/M, 15 MLL, 8 NOS, and 2 Ph+ (fig. 2). Samples were studied by whole genome and/or exome, RNA sequencing, and SNP array analysis. 44 multi-lineal samples were flow sorted into 2-4 lymphoid, myeloid, and ambiguous subpopulations (15 T/M, 19 B/M, 7 MLL, 1 Ph+, 2 NOS) and subjected to exome sequencing and SNP array. Mutational data were compared to data from 196 AML, 39 ETP-ALL, and 245 T-ALL cases. Results: We identified 35 recurrently mutated genes, the most common of which were WT1 (21%), FLT3 (18%), NRAS (16%), JAK3 (11%), RUNX1 (11%), KMT2D (9%), PTPN11 (9%), ASXL1 (7%), and CREBBP (7%). T/M and B/M subtypes are characterized by distinct patterns of genomic alteration. 48% of T/M cases harbored in-frame chimeric fusion, several of which are described in T-ALL, including ETV6-NCOA2 and ZEB2-BCL11B, NUP214-ABL1 and PICALM-MLLT10, and novel fusions involving hematopoietic regulators (e.g. ETV6-MAML and MNX1-IKZF1). 42% of B/M cases had in-frame fusions of ZNF384 with CREBBP, EP300, and TCF3, while we also identified isolated fusions involving ERG and NF1. Mutations of Ras signaling genes were present in 50% of B/M cases, in contrast to 10% of T/M cases. Epigenetic modifying genes, including CREBBP, SETD2, KMT2D, EZH2 and SUZ12 were mutated in 45% of the combined T/M and B/M cohorts. Cases with MLL gene rearrangements had few sequence alterations. In comparison to other subtypes of leukemia, the mutational spectrum of T/M MPAL, with alterations in transcription factors (60% cases), epigenetic genes (50%) and JAK-STAT signaling (35%) was more similar to ETP-ALL (64%, 72%, 44%) and T-ALL (49%, 60%, 21%) than to AML (19%, 21%, 11%). Similarly, B/M cases have increased alterations in these pathways (42%, 42%, 25%) compared to AML. Sequencing of MPAL subpopulations revealed that 27% of cases had the same SNVs/indels in each subpopulation, and 47% of cases had at least two-thirds of mutations present in each subpopulation. All multi-lineal cases with alterations of regulators WT1 and RUNX1 showed similar allele frequencies of these mutations in all populations. Alternatively, cases with mutations in signaling (FLT3, NRAS, KRAS, PTPN11) or epigenetic regulatory genes (CREBBP, KMT2D, SETD2) only showed consistent presence of alterations across each subpopulation in 60% of the cases. Conclusions: Our analysis has shown that T/M and B/M MPAL are distinct subtypes of leukemia. B/M MPAL is characterized by frequent RAS pathway mutations and ZNF384 fusions with multiple different fusion partners, suggesting that this gene plays a critical role in hematopoietic development for progenitor cells with B lymphoid and myeloid potential. The findings of mutational similarity to ETP ALL, and sharing of genomic lesions between subclones in the majority of cases strongly suggests that MPAL represents part of a spectrum of immature leukemias that arise in a hematopoietic progenitors that may propagate multiple immunophenotypic populations. These results will guide the design of therapeutic strategies for each subtype of MPAL and ETP ALL, and xenografts representative of each subtype are being used to examine sensitivity to therapeutic agents. Figure 1 Figure 1. Figure 2 Figure 2. Disclosures Loh: Abbvie: Research Funding; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Zwaan:Pfizer: Research Funding; Pfizer: Consultancy. Reinhardt:Pfizer: Membership on an entity's Board of Directors or advisory committees; Celgene: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees; Boehringer Ingelheim: Membership on an entity's Board of Directors or advisory committees; Jazz Pharma: Other: Travel Accomodation. Inaba:Arog: Research Funding. Mullighan:Loxo Oncology: Research Funding; Incyte: Membership on an entity's Board of Directors or advisory committees; Amgen: Speakers Bureau.

7023 Background: MPAL is a rare subgroup of acute leukemia characterized by both myeloid and lymphoid phenotypes. Genetic basis of MPAL is not well understood. Methods: We studied 31 patients (pts) with MPAL (median age 53) that met 2008 WHO criteria. Bone marrow samples were studied by targeted capture sequencing of 295 genes (median 393x), RNA sequencing, and Infinium methylation EPIC array (Illumina). Mutational landscape was compared to 194 AML, 71 B-ALL, and 6 T-ALL cases. Promoter methylation pattern was compared to the data from 194 AML (TCGA), 505 B-ALL and 101 T-ALL cases (Nordlund et al. Genome Biology. 2013). Results: Eighteen (58%) pts had myeloid-T and 13 (42%) had myeloid-B phenotype. Four pts had t(9;22), 1 had 11q23 rarrangement, and 8 had complex karyotype. MPAL had similar number of mutations with AML but had higher number of mutations than B-ALL or T-ALL. Both AML-type and ALL-type mutations were detected in MPAL, supporting the mixed phenotypic features. However, NPM1, CEBPA and GATA2 mutations were specific to AML and were not found in MPAL. Myeloid-T and myeloid-B showed distinct patterns of mutations, in which DNMT3A, IDH2, NOTCH1, IL7R, and FBXW7 mutations were enriched in myeloid-T whereas RUNX1 mutations were enriched in myeloid-B. Myeloid-T and myeloid-B also showed distinct patterns of promoter methylation. Overall, myeloid-T had more hypermethylated CpG loci than myeloid-B. Genes that have essential role in T-cell receptor (TCR) pathway ( CD3D, CD7, CD247, LCK, PRKCQ, CCR9, and TCL1A) were differentially methylated and differentially expressed between myeloid-T and myeloid-B. RNA sequencing revealed several known translocations such as, NSD1-NUP98, and KMT2A-MLLT4, in addition to the novel fusion proteins such as FOXP1-DNAJC15, RUNX1-NAP1L1, and BCL2-TM9SF3. Unbiased hierarchical clustering of MPAL, AML, B-ALL and T-ALL by promoter methylation revealed that myeloid-T had consistent similarity with T-ALL, while myeloid-B showed random similarity with either B-ALL or AML. Conclusions: MPAL is genetically heterogeneous and myeloid-T and myeloid-B shows distinct patterns of mutations, methylation and gene expressions. Therapy for MPAL may need to be tailored based on the genetic profiles.

Background: Myeloid and lymphoid leukemias each have distinct diagnostic algorithms, treatment paradigms, and therapeutic options. In mixed phenotype acute leukemia (MPAL), myeloid and lymphoid immunophenotypes are expressed simultaneously. MPAL is rare, accounting for fewer than 5% of all leukemias, and carries a poor prognosis. Currently, there is no standard of care for treatment of this disease and therapeutic options tailored to this group of patients are lacking. Additionally, the biological mechanisms underlying lineage infidelity are poorly understood. Here we seek to establish more precise biological characterization of this disease and have identified a new subgroup of patients with Mixed Phenotype Acute Myeloid Leukemia (AML-MP). Methods: We developed a novel natural language processing pipeline and used it to review 830 patient records, representing all acute leukemia patients treated at Memorial Sloan Kettering Cancer Center since 2015. We identified those with ambiguous lineages based on multiparameter flow cytometry data and integrated next-generation sequencing, cytogenetics, and clinical information. Statistical methods are outlined with the associated results below. Results: Among the 830 patient records reviewed, 54 (6.5%) patients with mixed lineage characteristics were identified. Of these, 26 (48%) carried a formal diagnosis of MPAL while 28 (52%) carried a diagnosis of AML with myelodysplasia related changes (AML-MRC) or therapy related AML (t-AML). Among the cases expressing multiple lineages, 34 (25%) had B/Myeloid features (11 MPAL, 23 AML-MRC), 17 (13%) had T/Myeloid features (13 MPAL, 4 AML-MRC), 3 (0.7%) had B/T/Myeloid lineage (2 MPAL, 1 AML-MRC). Only 8 patients received prior chemotherapy at our institution > 1 year prior to diagnosis and were classified as t-AML. As a control group, we also identified 79 patients with AML-MRC exhibiting myeloid lineage alone. We pooled the mixed-lineage and myeloid-only AML-MRC cases and performed k-means clustering into 2 groups using all available molecular features (Figure 1a). Although TP53 was enriched within AML cases (p<0.01), it was insufficient either individually or in combination with other mutations to significantly distinguish AML from MPAL cases (p=1). Among patients with mixed lineage characteristics, we performed a cox proportional hazards analysis and found that RUNX1 and SRSF2 mutations were predictors of better overall survival (OS) after adjusting for age, cytogenetics, and diagnosis type (age > 60: p < 0.01, high risk cytogenetics: p<0.08, intermediate risk cytogenetics: p=0.02, RUNX1: p<0.01, SRSF2: p=0.03; overall: p < 0.01; Figure 1b, left). An MPAL diagnosis by WHO criteria failed to achieve independent statistical significance on its own (p=0.57). Among AML-MRC myeloid only cases, ASXL1 mutation was associated with improved OS and TET2 mutation showed a trend toward poorer OS after adjusting for age and cytogenetic risk (age>60: p=0.01, ASXL1: p=0.02, TET2: p=0.06; overall: p < 0.01, Figure 1b, right). Cytogenetic risk did not independently contribute to the model (high risk: p=0.3, intermediate risk: p=0.55). We also manually reviewed flow cytometry results from 64 patients diagnosed with MPAL or diagnosed with t-AML or AML-MRC despite expressing markers of multiple lineages (Mixed Phenotype AML). Using a k-nearest neighbor approach, we found that immunophenotype identified two distinct patient populations - one largely Mixed Phenotype AML, and the other with a mixture of MPAL and Mixed Phenotype AML cases (p<0.01) (Figure 1c). Conclusions: Genomic characteristics improve prognostication for patients with MPAL, with RUNX1 and SRSF2 predicting a more favorable OS and TP53 not predictive of worse OS; this is in contrast to current stratifications of patients with de novo AML. While TP53 is enriched among AML cases, it does not distinguish AML-MRC from MPAL. Additionally, AML-MRC patients with ASXL1 mutations had improved overall survival after adjusting for cytogenetic risk. Some cases that are categorized as AML-MRC and t-AML by WHO criteria should be considered Mixed Phenotype AML and may be better classified into one of two distinct immunophenotypic subsets. Our study and model provide a more refined biological classification and prognostic schema for patients with MPAL and AML-MP; further validation of these observations is required in other data sets. Figure 1 Disclosures Roshal: Auron Therapeutics: Equity Ownership, Other: Provision of services; Celgene: Other: Provision of Services; Physicians' Education Resource: Other: Provision of services. Levine:Prelude Therapeutics: Research Funding; Roche: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Gilead: Consultancy; Qiagen: Membership on an entity's Board of Directors or advisory committees; C4 Therapeutics: Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy; Loxo: Membership on an entity's Board of Directors or advisory committees; Isoplexis: Membership on an entity's Board of Directors or advisory committees; Imago Biosciences: Membership on an entity's Board of Directors or advisory committees; Lilly: Honoraria; Amgen: Honoraria. Tallman:Indy Hematology Review: Honoraria; Hematology Oncology of Indiana: Honoraria; Salzberg Weill Cornall MSKCC Seminar in Hematologic Malignancies: Honoraria; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding; International Conference in Leukemia: Honoraria; 14th Annual Miami Cancer Meeting: Honoraria; Amgen: Consultancy; Orsenix: Membership on an entity's Board of Directors or advisory committees, Research Funding; UpToDate: Patents & Royalties; Mayo Clinic: Honoraria; New Orleans Summer Cancer Conference: Honoraria; ADC Therapeutics: Research Funding; Danbury Hospital Tumor Board: Honoraria; Arog Pharmaceuticals: Research Funding; Nohla: Membership on an entity's Board of Directors or advisory committees, Research Funding; KAHR: Membership on an entity's Board of Directors or advisory committees; Daiichi-Sankyo: Membership on an entity's Board of Directors or advisory committees; BioSight: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bioline: Membership on an entity's Board of Directors or advisory committees, Research Funding; University of Oklahoma Medical Center: Honoraria; Cellerant Therapeutics: Research Funding; Rigel: Membership on an entity's Board of Directors or advisory committees.

Mixed phenotype acute leukemia (MPAL) is a rare form of acute leukemia comprising 2% to 3% of all acute leukemia diagnoses. The diagnosis of MPAL is based on flow cytometric analysis of the immunophenotype, which demonstrates expression of differentiation-related antigens belonging to multiple lineages commonly, one lineage is myeloid and the other is B and/or T lymphoid. Whether lineage differentiation determines clinical presentation and outcomes is unclear. Here we report a case of 37 years old man who presented with leukocytosis & found to have MPAL (mixed phenotype acute leukemia) with possible differentiation to 3 lineages as evident by flowcytometry cases with trilineage antigenic determinants are very rare.

Great progress has been achieved in the diagnostics and therapy of childhood acute lymphoblastic leukemia (ALL) during the last few decades and the permanent cure rate for children and adolescents has risen to nearly 90%. The basic principle of ALL treatment is to split patients into several groups receiving treatment of different intensity according to exactly defined prognostic features. This is aimed at reducing both the risk of relapse and toxic complications of treatment. The development of new diagnostic methods, especially in the field of molecular genetics and flow cytometry, allowed further improvements in the risk stratification - the minimal residual disease (MRD) has become a crucial prognostic factor in modern treatment protocols for pediatric ALL as a sensitive marker of both response to therapy and subclinical leukemic involvement of various tissues of the organism. Nevertheless, there is still an intensive search for new markers that would enable even more precise characterization of the leukemic clone, and treatment strategies reflecting the biology of leukemic cells are being optimized. The first part of our study describes the monitoring and prognostic impact of MRD in peripheral blood of children with ALL with emphasis on very early time points of treatment. MRD was examined by the...