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Background: The apparent lack of additional missense mutations data on mixed-phenotype leukemia is noteworthy. Single amino acid substitution by these non-synonymous single nucleotide variations can be related to many pathological conditions and may influence susceptibility to disease. This case-control study aimed to unravel whether the ZAP70 missense variant (rs104893674 (C > A)) underpinning mixed-phenotype leukemia. Methods: The rs104893674 was genotyped in clients who were mixed-phenotype acute leukemia-, acute lymphoblastic leukemia- and acute myeloid leukemia-positive and matched healthy controls, which have been referred to all major urban hospitals from multiple provinces of country- wide, IRAN, from February 11' 2019 to June 10' 2023, by amplification refractory mutation system-polymerase chain reaction method. Direct sequencing for rs104893674 of the ZAP70 gene was performed in a 3130 Genetic Analyzer. Results: We found that the AC genotype of individuals with A allele at this polymorphic site (heterozygous variant-type) contribute to the genetic susceptibility to acute leukemia of both forms, acute myeloid leukemia and acute lymphoblastic leukemia as well as with a mixed phenotype. In other words, the ZAP70 missense variant (rs104893674 (C > A)) increases susceptibility of distinct cell populations of different (myeloid and lymphoid) lineages to exhibiting cancer phenotype. The results were all consistent with genotype data obtained using a direct DNA sequencing technique. Conclusion: Of special interest are pathogenic missense mutations, since they generate variants that cause specific molecular phenotypes through protein destabilization. Overall, we discovered that the rs104893674 (C > A) variant chance in causing mixed-phenotype leukemia is relatively high. [ABSTRACT FROM AUTHOR]

Introduction: Mixed-phenotype acute leukemia (MPAL) is a rare disease with poor prognosis. So far, no standard approach has been established as the "knowhow" of MPAL is based only on retrospective analyses performed on small groups of patients. Materials and methods: In this study, a retrospective analysis of the outcomes of adult MPAL patients included in the PALG registry between 2005 and 2024 who received the CLAG-M hybrid protocol as induction or salvage therapy was performed. Results: Sixteen of 98 MPAL patients received CLAG-M: eight as first-line and eight as salvage therapy. In the first line, two patients achieved partial response (PR), and six achieved complete remission (CR), of whom four successfully underwent allogeneic hematopoietic stem cell transplantation (alloHSCT). Two patients who did not undergo alloHSCT promptly relapsed. Within the whole group, the overall response rate (ORR) was 75% (n = 12/16). With the median follow-up of 13 months, six out of eight patients remain in CR, however, two of them died due to acute graft versus host disease. Out of eight patients who received CLAG-M in the second line, four patients (50%) obtained CR. AlloHSCT was conducted in seven cases, six of which were in CR. Only two patients remained in CR at the time of the last follow-up. Tolerance to treatment was good. The median times for severe neutropenia and thrombocytopenia were 22 days (range, 16-24) and 17 days (range, 12-24), respectively. Overall, grade 3-4 infections were observed in 12 cases, and all infections presented successful outcomes. Conclusions: CLAG-M is an effective first-line salvage regimen for MPAL with an acceptable safety profile. Early achievement of CR with prompt alloHSCT allows for satisfactory disease control. [ABSTRACT FROM AUTHOR]

While our understanding of the molecular basis of mixed phenotype acute leukemia (MPAL) has progressed over the decades, our knowledge is limited and the prognosis remains poor. Investigating cases of familial leukemia can provide insights into the role of genetic and environmental factors in leukemogenesis. Although familial cases and associated mutations have been identified in some leukemias, familial occurrence of MPAL has never been reported. Here, we report the first cases of MPAL in a family. A 68-year-old woman was diagnosed with MPAL and received haploidentical stem cell transplantation from her 44-year-old son. In four years, the son himself developed MPAL. Both cases exhibited similar characteristics such as biphenotypic leukemia with B/myeloid cell antigens, Philadelphia translocation (BCR-ABL1 mutation), and response to acute lymphoblastic leukemia-type chemotherapy. These similarities suggest the presence of hereditary factors contributing to the development of MPAL. Targeted sequencing identified shared germline variants in these cases; however, in silico analyses did not strongly support their pathogenicity. Intriguingly, when the son developed MPAL, the mother did not develop donor-derived leukemia and remained in remission. Our cases provide valuable insights to guide future research on familial MPAL. [ABSTRACT FROM AUTHOR]

Background: Mixed phenotype acute leukemia (MPAL), a rare subgroup of leukemia characterized by blast cells with myeloid and lymphoid lineage features, is difficult to diagnose and treat. A better characterization of MPAL is essential to understand the subtype heterogeneity and how it compares with acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL). Therefore, we performed single-cell RNA sequencing (scRNAseq) on pediatric MPAL bone marrow (BM) samples to develop a granular map of the MPAL blasts and microenvironment landscape. Methods: We analyzed over 40,000 cells from nine pediatric MPAL BM samples to generate a single-cell transcriptomic landscape of B/myeloid (B/My) and T/myeloid (T/My) MPAL. Cells were clustered using unsupervised single-cell methods, and malignant blast and immune clusters were annotated. Differential expression analysis was performed to identify B/My and T/My MPAL blast-specific signatures by comparing transcriptome profiles of MPAL with normal BM, AML, and ALL. Gene set enrichment analysis (GSEA) was performed, and significantly enriched pathways were compared in MPAL subtypes. Results: B/My and T/My MPAL blasts displayed distinct blast signatures. Transcriptomic analysis revealed that B/My MPAL profile overlaps with B-ALL and AML samples. Similarly, T/My MPAL exhibited overlap with T-ALL and AML samples. Genes overexpressed in both MPAL subtypes' blast cells compared to AML, ALL, and healthy BM included MAP2K2 and CD81. Subtype-specific genes included HBEGF for B/My and PTEN for T/My. These marker sets segregated bulk RNA-seq AML, ALL, and MPAL samples based on expression profiles. Analysis comparing T/My MPAL to ETP, near-ETP, and non-ETP T-ALL, showed that T/My MPAL had greater overlap with ETP-ALL cases. Comparisons among MPAL subtypes between adult and pediatric samples showed analogous transcriptomic landscapes of corresponding subtypes. Transcriptomic differences were observed in the MPAL samples based on response to induction chemotherapy, including selective upregulation of the IL-16 pathway in relapsed samples. Conclusions: We have for the first time described the single-cell transcriptomic landscape of pediatric MPAL and demonstrated that B/My and T/My MPAL have distinct scRNAseq profiles from each other, AML, and ALL. Differences in transcriptomic profiles were seen based on response to therapy, but larger studies will be needed to validate these findings. [ABSTRACT FROM AUTHOR]

Adult B-lineage acute lymphoblastic leukemia (B-ALL) with t(4;11)(q21;q23) is very rare. It is characterized by mixed-lineage leukemia and has the potential for lineage switching during the treatment course. We report the disease course of a patient with B-ALL with t(4;11)(q21;q23) to demonstrate that close monitoring of cell morphology and immunophenotyping is necessary to capture the lineage switch at an early stage. Cell morphology, immunophenotyping, and cytogenetics were used to evaluate the patient's disease status. A 36-year-old woman was diagnosed with B-ALL with t(4;11)(q21;q23), which encodes the KMT2A::AFF1 fusion. After the initial induction chemotherapy, her disease remained refractory, and the patient received salvage immunotherapy with blinatumomab and inotuzumab ozogamicin. However, the ALL did not respond. Repeated bone marrow examinations unexpectedly revealed the emergence of a major population of monoblasts, in addition to a minor population of the original B lymphoblasts. The patient was diagnosed with disease evolution from B-ALL to mixed-phenotype acute leukemia (MPAL, B/myeloid). We present this case to highlight the potential of KMT2A-rearranged B-ALL to undergo lineage switch following B-cell targeted therapy. Patients with this kind of B-ALL should therefore be closely monitored to capture potential changes in the nature of the disease and prompt appropriate treatment. [ABSTRACT FROM AUTHOR]

Introduction: Myeloperoxidase (MPO) is considered a specific marker of myeloid/non‐monocytic lineage in the diagnosis of mixed phenotype acute leukemia (MPAL). However, the clinical significance of isolated dim MPO expression in otherwise typical B lymphoblastic leukemia (B‐ALL; referred to as B/myeloid MPALisoMPO) in adult patients is unknown. Methods: We compared flow cytometric immunophenotype and clinicopathological findings among cases of B/myeloid MPALisoMPO (n = 13), other MPAL subtypes (n = 10, B/myeloid and T/myeloid MPAL), B‐ALL (n = 64), and acute myeloid leukemia (AML, n = 58), using the 2016 WHO classification. For MPAL cases, MPO was reported as the percent of MPO positive blasts and its intensity (dim or moderate/strong). The pattern of heterogenous antigen expression (inversely coordinated expression between myeloid and lymphoid markers and cell size) was assessed. Results: Cases of B/myeloid MPALisoMPO showed a fairly homogenous single B‐lineage blast population with dim MPO expression whereas cases of other MPAL subtypes displayed heterogeneous antigen expression and moderate/strong MPO expression. The percent of MPO positive blasts in these two groups was similar. Expressions of CD15, CD117, and monocytic markers were more common in other MPAL than in B/myeloid MPALisoMPO. B/myeloid MPALisoMPO patients had similar overall and leukemia free survivals as B‐ALL patients and better than other MPAL patients. Conclusion: This is the first study to investigate the clinical significance of adult B/myeloid MPALisoMPO using the 2016 WHO classification. Our results suggest that B/myeloid MPALisoMPO clinically behaves more similarly to B‐ALL than to other MPAL subtypes, supporting the 2016 WHO classification to segregate this entity from other MPAL subtypes. [ABSTRACT FROM AUTHOR]

Keywords: Acute lymphoblastic leukemia; Mixed phenotype acute leukemia; Daratumumab; Venetoclax EN Acute lymphoblastic leukemia Mixed phenotype acute leukemia Daratumumab Venetoclax 669 672 4 03/03/23 20230301 NES 230301 Dear Editor: Here, we report on a twelve-year-old boy diagnosed with mixed phenotype acute leukemia (T cell ALL/acute myeloid leukemia, AML) bearing a I KMT2A::MLLT4 i fusion in June 2018. In the further course, the patient received low-dose cytarabine, two additional DLI doses, and mistletoe therapy. 1 Treatment course of a patient with with KMT2A:MLLT4-positive mixed phenotype acute leukemia (T cell ALL/AML). [Extracted from the article]

Background: The goal was to improve the understanding of mixed phenotypic acute leukemia (MPAL) complicated with plasmacytoid dendritic cell (PDC) proliferation. Methods: A case of mixed phenotype acute leukemia with plasmacytoid dendritic cell hyperplasia was reported. The clinical characteristics, treatment, and prognosis were analyzed by reviewing relevant literature. Results: The patient was a young female with clinical manifestations of splenomegaly and lymph node enlargement. The bone marrow smear showed hyperactive proliferation, 95% of protoblastic cells. The protoblastic cell body is large, more cell mass, stained gray blue, a small amount of azurophilicgranule can be seen in some cytoplasm, pseudopodia, drag tail, and other phenomena. The nucleus was twisted and folded. Chromatin is fine with nucleoli and Auer rods seen in the cytoplasm. Immune typing: Abnormal primordial cells accounted for 44.75%, and the primordial cells expressed both myeloid markers (CD33, CD13, MPO) and T-series markers (CD7, CD5, Ccd3), which were considered MPAL (M/T) according to WHO diagnostic criteria. In addition, a group of plasmoid dendritic cells occupied an increased proportion of 10.31% of nuclear cells. No obvious phenotypic abnormalities were observed. BCR/ABL fusion genes P190/P210 were negative. NRAS, NOTCH1, and DNMT3A mutations were detected by polymerase chain reaction. Combined with the above results, acute mixed cell leukemia (M/T) with plasmacytoid dendritic cell proliferation was diagnosed. Conclusions: The diagnosis of mixed phenotype acute leukemia with plasmacytoid dendritic cell proliferation needs to be integrated with clinical manifestations, cytomorphology, immunology, cytogenetics, and molecular biology, etc. Disease should be diagnosed and treated as early as possible. [ABSTRACT FROM AUTHOR]

The epidemiology of infant acute lymphoblastic leukemia (ALL), hypodiploid ALL, and mixed-phenotype acute leukemia (MPAL) in Canada is unknown. The main objective was to describe the prevalence, prognostic factors, and outcomes of three rare and high-risk ALL subtypes in Canada. This is a retrospective study using the Cancer in Young People-Canada (CYP-C) database. Event-free survival (EFS) and overall survival (OS) were described by the Kaplan–Meier method and compared using the log-rank test. Among 2626 children aged 0–14 years diagnosed with B-cell acute lymphoblastic leukemia (B-ALL) between 2001 and 2018, 227 (8.6%) patients were identified to be infant ALL (n = 139), hypodiploid ALL (n = 43), or MPAL (n = 45). The 5-year EFS/OS was significantly worse in the infant ALL subgroup compared to that of hypodiploid ALL and MPAL. For the entire cohort, presenting White blood cells (WBCs) ≥50 × 109/L was independently associated with worse EFS/OS. [ABSTRACT FROM AUTHOR]

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is a heterogeneous malignancy and consists of several genetic abnormalities. Some of these abnormalities are used in clinics for risk calculation and treatment decisions. Patients with ZNF384 rearrangements had a distinct expression profile regardless of their diagnosis, BCP-ALL or mixed phenotype acute leukemia (MPAL) and defined as a new subtype of ALL. In this study, we screened 42 MPAL and 91 BCP-ALL patients for the most common ZNF384 fusions; ZNF384::TCF3, ZNF384::EP300 and ZNF384::TAF15 by using PCR. We identified ZNF384 fusions in 9.5% of MPAL and 7.6% of BCP-ALL. A novel breakpoint was identified in ZNF384::TCF3 fusion in one BCP-ALL patient. T-myeloid MPAL patients showed significantly lower ZNF384 expression compared to lymphoid groups. Patients with ZNF384r had intermediate survival rates based on other subtypes. Prognostic and patient-specific treatment evaluation of ZNF384 fusions in both ALL and MPAL might help to improve risk characterization of patients. [ABSTRACT FROM AUTHOR]

Background: The diagnosis of mixed phenotype acute leukemia (MPAL) with T/megakaryocyte or T/myeloid lineages accompanied by t(3;3) is always a challenge. Therefore, multiple experimental methods are usually required to avoid misdiagnosis. In this report, we presented a rare case of MPAL with T/myeloid lineages accompanied by t(3;3) and discussed the experience of differential diagnosis and our appreciation of the MPAL with T/megakaryocyte and T/myeloid lineages accompanied by t(3;3). Case presentation: A 31-year-old woman was admitted to our hospital due to recurrent fever for 20 days. Two distinct blast populations were detected by flow cytometry analysis: one population fulfills the immunophenotypic criteria for T-lymphoblastic leukemia, while the other population is highly suggestive of megakaryoblasts. These immunophenotypic features support the diagnosis of MPAL (T/megakaryocyte), which is rarely reported​. Interestingly, a complex karyotype was detected afterward by cytogenetics with t(3;3)(q21;q26.2), indicating a diagnosis of AML with t(3;3), a subset of which is also characterized by megakaryocytic markers such as CD41 and CD61. It seems that the second blast population detected by flow cytometry could not be classified into either diagnosis based on the morphology, immunophenotyping, and even cytogenetic findings, posing a real diagnostic problem because of the lack of clear-cut cytogenetic morphological defined criteria to distinguish between acute megakaryocytic leukemia and AML with t(3;3). Combining all of the examination data, this case was ultimately diagnosed as MPAL (T + My)-NOS with t(3;3) through differential diagnosis. Before the cytogenetic results were available, the patient received an acute lymphoblastic leukemia (ALL) regimen for MPAL treatment, but the effect was unsatisfactory. After the diagnosis was clear, she received an AML-like regimen with azacitidine for 7 days and venetoclax for 14 days, and achieved complete morphological remission. Conclusion: MPAL with either T/megakaryocyte or T/myeloid lineages accompanied by t(3;3) is rare, and it is difficult to make a clear diagnosis. Thus, comprehensive examinations, including bone marrow cell morphology, flow cytometry analysis, cytogenetics, and molecular analysis are recommended to avoid misdiagnosis. AML-like regimen including azacitidine and venetoclax may be effective for treating MPAL (T + My)-NOS with t(3;3). [ABSTRACT FROM AUTHOR]

A 60-year-old female presented with acute onset painless loss of vision in both eyes. Clinical examination and ocular investigations revealed bilateral serous retinal detachments (SRDs) over the macula. There was no obvious intraocular or extraocular cause to the presentation. A blood count showed leukocytosis with the presence of blast cells on the peripheral smear. Further workup confirmed the diagnosis of Philadelphia chromosome-positive mixed phenotype acute leukemia with central nervous system disease stage three. Anatomic improvement in the SRD followed intensive intravenous and intrathecal chemotherapy. Limited functional improvement was attributed to the development of pigment epitheliopathy manifesting as leopard spot chorioretinopathy. This permanent disturbance could be attributed to leukemic infiltration and ischemia to the choroid. [ABSTRACT FROM AUTHOR]

Background: Mixed-phenotype acute leukemia (MPAL) in children Is an uncommon subtype of acute leukemia that cannot be definitively assigned to a specific lineage. There is no consensus on the best approach to therapy. Management is more complex in low-middle-income countries (LMICs). Aim: To evaluate the clinicopathological characteristics and outcomes of patients with MPAL in a developing country. Patients and Methods: A retrospective descriptive study of 42 pediatric patients newly diagnosed with MPAL from July 2007 until December 2017. Results: The immunophenotyping was T/Myeloid in 24 patients (57.1%) and B/Myeloid in 16 (38.1%). Three subjects had MLL gene rearrangement, two had Philadelphia-positive chromosomes, and eight had FMS-like tyrosine kinase 3 (FLT3-ITD) internal tandem duplication (FLT3-ITD) with a ratio >0.4. Two subjects died before starting chemotherapy. Ten patients (25%) received acute lymphoblastic leukemia (ALL) induction, and all achieved complete remission (CR) with no induction deaths and no shift of therapy. Thirty patients (75%) started therapy with acute myeloid leukemia (AML) induction: five (16.6%) died during induction, 17 (56.7%) achieved CR, and 10 patients received maintenance ALL therapy after ending AML treatment. Four of the eight patients with induction failure were switched to ALL therapy. The 5-year event-free survival (EFS) and overall survival (OS) rates were 56.7% [standard error (SE): 8.1%] and 61% (SE: 8%), while the cumulative incidence of relapse was 21.7% (SE: 6.7%), with a median follow-up duration of 5.8 years. Patients treated with ALL-directed therapy had a 5-year EFS rate of 111 70% (SE: 14%) and OS rate of 78.8% (SE: 13%). Patients treated with ALL-directed therapy had a 5-year EFS rate of 70% (SE: 14.5%) and OS rate of 78.8% (SE: 13%). FLT3-ITD mutation showed a significantly lower 5-year EFS rate of 28.6% (SE: 17%) vs. 75% (SE: 9%) for the wild type, p = 0.032. Undernourished patients with a body mass index (BMI) z-score ≤-2 at presentation had a significantly lower 5-year EFS rate of 20% (SE: 17%) compared to 61.8% (SE: 8%) for patients with BMI z-score >-2, p = 0.015. Conclusion: This study supports ALL-directed therapy for pediatric MPAL in a setting of LMIC. Given the poor outcome of FLT3-ITD, the role of FLT3 inhibitor needs to be explored in this subset of cases. [ABSTRACT FROM AUTHOR]

A combination of azacitidine and venetoclax (AZA-VEN) has been approved for the treatment of adult treatment-naïve acute myeloid leukemia (AML) patients, ineligible for intensive chemotherapy. The protocol may also constitute an alternative for the treatment of patients with mixed phenotype acute leukemia (MPAL), for which no established treatment guidelines exist. It may be anticipated, that alike in AML or chronic lymphocytic leukemia, the treatment of MPAL may be complicated by the tumor lysis syndrome (TLS). No case of TLS in MPAL after VEN has been however reported so far. Here, we present a case of a patient with MPAL, who received AZA-VEN. The patient had a substantial bulk of disease with generalized lymphadenopathy and increased white blood cell count. Despite preventive measures, the patient developed the clinical TLS, which was successfully treated. Based on the current case and other published cases, the incidence of TLS after AZA-VEN was established at 17%. [ABSTRACT FROM AUTHOR]

Chronic neutrophilic leukemia (CNL) relates to mutational CSF3R activation with membrane proximal CSF3R mutations such as T618I as driver mutations, but the significance of truncating mutations is not clarified. In CNL, concomitant mutations promote disease progression, but insight into longitudinal acquisition is incomplete. In this study, we investigated the role of co-occurring germline and somatic CSF3R mutations in CNL, and assessed the impact of clonal evolution on transformation to acute leukemia. We employed sequential next generation sequencing and SNP array karyotyping to assess clonal evolution in CNL of early manifestation age based on a 33-year-old patient. Germline vs. somatic mutations were differentiated using a sample from the hair follicle. To investigate a potential predisposition for CNL development and progression by germline CSF3R-W791*, allelic localizations were evaluated. We detected a somatic CSF3R-T618I mutation at 46% variant allele frequency (VAF) at the time of CNL diagnosis, which co-occurred with a CSF3R-W791* truncation at 50% VAF in the germline. Evaluation of allelic localization revealed CSF3R-T618I and W791* on the same allele. A concomitant ASXL1 mutation at 39% VAF increased to 48% VAF upon transformation to mixed phenotype acute leukemia (MPAL), which has both myeloid and lymphoid features. Clonal evolution further involved expansion of the CSF3R double-mutant clone to 90% VAF via copy neutral loss of heterozygosity on chromosome 1p and the emergence of a RUNX1 mutant subclone. Allogeneic transplantation induced complete remission. This study highlights that CNL not only transforms to AML but also to MPAL. The molecular evolution is especially interesting with a CSF3R-W791* mutation in the germline and acquisition of CSF3R-T618I on the same allele compatible with increased susceptibility for mutation acquisition facilitating RUNX1-related clonal transformation. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is an uncommon disease characterized by currently only limited knowledge concerning biology, clinical presentation, and treatment outcome. We here describe a most unusual case of simultaneous occurrence of T-lymphoblastic lymphoma in cervical and mediastinal lymph nodes and acute myeloid leukemia in the bone marrow (BM) successfully treated with allogeneic stem cell transplantation (SCT). Although the blasts in both locations showed additional aberrant expression of other lineage markers (even B-cell markers), diagnostic criteria of MPAL were not fulfilled either in the LN or in the BM. We performed next generation sequencing (NGS) with the objective to look for common genetic aberrations in both tissues. Histology, immunohistochemistry, flow cytometry, AML-associated genetic alterations (FLT3, NPM1, KIT D816V, CEPBA), and clonal T-cell receptor β and γ gene rearrangements were performed according to routine diagnostic workflows. Next generation sequencing and Sanger sequencing were additionally performed in BM and LN. Somatic mutation in the EZH2 gene (p.(Arg684Cys)) was detected in the BM by NGS, and the same mutation was found in the LN. Since an identical genetic aberration (EZH2 mutation) was detected in both locations, a common progenitor with regional dependent differentiation may be involved. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is a heterogeneous group of leukemias that are defined immunophenotypically by antigen expression on blasts of both myeloid and lymphoid lineage. With the exception of BCR-ABL positive and KMT2A rearranged MPAL, the biology of the majority of MPAL remains uncertain. Several recent studies have explored the genomic and epigenetic landscape of MPAL and have suggested a further refinement of the WHO classification to emphasize the genomic heterogeneity of MPAL. Further studies including single cell analysis, whole exome sequencing and time of flight cytometry will provide for further biological characterization. Treatment decisions are complicated due to this lack of classification and the dearth of prospective randomized studies. Acute lymphoblastic leukemia-type therapy appears to achieve higher remission rates, and allogenic stem cell transplantation may be beneficial in a select group of patients in first complete remission. Multi-center collaborations may answer these questions more conclusively. Our review aims to discuss the diagnostic challenges, recent genomic studies and therapeutic strategies in this poorly understood disease. [ABSTRACT FROM AUTHOR]

There is limited data regarding pediatric mixed phenotype acute leukemia (MPAL) and there is no global consensus on its management yet. In this retrospective study, we analyzed the outcomes of children diagnosed with MPAL at our institute. This study included children ≤ 14 years with MPAL who presented to a tertiary cancer center in India from January 1st 2009 to December 31st 2015. Over a seven-year period, 1390 patients with leukemia presented to our institute of which 22 patients (1.5%) had MPAL. Sixteen patients (72.7%) had B/myeloid leukemia, while 4 (18.1%) and 2 (9%) patients had T/myeloid and B/T leukemia respectively. Twenty-one patients were treated with a modified BFM ALL 95 protocol. 76.1% (n = 16) of patients had a good prednisolone response (GPR) on day 8 and end-of-induction (EOI) marrow was in remission in 90.5% (n = 19). A poor prednisolone response (PPR) on day 8 correlated with an inferior relapse-free survival (25% vs 79.5%, P=.025). The 4-year event-free survival (EFS) and overall survival (OS) for the entire group was 60.8% and 64.9% respectively while the EFS for patients who had a GPR and remission at the EOI (n = 15) was 80% as compared to 16.7% in patients with PPR or induction failure. Lymphoid directed chemotherapy is seen to have good survival outcomes in pediatric MPAL. However, a PPR on day 8 or a positive EOI marrow may be an indication for more aggressive treatment. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is a rare type of leukemia with a limited number of studies conducted to characterize its clinical spectrum and most importantly the best treatment modality. MPAL blasts show more than one phenotype either myeloid/monocytic with T- or B-lymphoid or extremely rare triple lineage associated phenotypic markers. This study aimed to characterize MPAL cases with special emphasis on comparing adult and pediatric age groups, exploring treatment regimens, and clinical outcome. Among 2571 acute leukemia patients, 102 MPAL cases fulfilling the 2008/2016 WHO diagnostic criteria of MPAL were recruited in the study. The incidence of MPAL was 4% of acute leukemia patients. Pediatric cases were 54 (53%) while adults were 48/102 (47%). Myeloid/B-lymphoid phenotype was found in 86/102 (84%), with BCR-ABL fusion gene transcript detected in 14/102(13.7%) patients. ALL-like treatment showed better response rates as compared with the myeloid based regimen (p = 0.001). MPAL behaves in a manner that resembles in clinical features, their lymphoid progenitor counterpart leukemias both in adults and pediatric patients with superior treatment response to ALL-like regimen, especially in adults. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) accounts for 2-5% of leukemia in children. MPAL are at higher risk of induction failure. Lineage switch (B to M or vice versa) or persistence of only the lymphoid or myeloid clone is frequently observed in biphenotypic/bilineal cases, highlighting their lineage plasticity. The prognosis of MPAL remains bleak, with an event-free survival (EFS) of less than 50% in children. A lymphoid-type therapeutic approach appears to be more effective but failures to achieve complete remission (CR) remain significant. KMT2A fusions account for 75-80% of leukemia in infants under one year of age and remains a major pejorative prognostic factor in the Interfant-06 protocol with a 6 years EFS of only 36%. The search for other therapeutic approaches, in particular immunotherapies that are able to eradicate all MPAL clones, is a major issue. We describe here the feasibility and tolerance of the combination of two targeted immunotherapies, blinatumomab and Gemtuzumab Ozogamicin, in a 4-year-old infant with a primary refractory KTM2A-rearranged MPAL. Our main concern was to determine how to associate these two immunotherapies and we describe how we decided to do it with the parents' agreement. The good MRD response on the two clones made it possible to continue the curative intent with a hematopoietic stem cell transplant at 9 months of age. Despite a relapse at M11 post-transplant because of the recurrence of a pro-B clone retaining the initial lymphoid phenotype, the child is now 36 months old, in persistent negative MRD CR2 for 12 months after a salvage chemotherapy and an autologous CAR T cells infusion, with no known sequelae to date. This case study can thus lead to the idea of a sequential combination of two immunotherapies targeting two distinct leukemic subclones (or even a single biphenotypic clone), as a potential one to be tested prospectively in children MPAL and even possibly all KMT2A-rearranged infant ALL. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is an uncommon type of leukemia. It is one kind of malignant clonal diseases that expresses more than one genealogical specific antigen simultaneously. Most MPAL patients are associated with clonal chromosomal abnormalities and molecular genetic changes, such as t(9;22) (q34;q11) and KMT2A (MLL) rearrangement. These specific abnormalities usually have important guiding significance in MPAL diagnosis, targeted therapy and prognosis judgment. In this paper, we reported a case of MPAL, T/myeloid (M5) with an unfrequent combination of PML-RARα positivity and t(15;17). The treatment was successful with chemotherapy for both AML and ALL with daunorubicin, cytarabine (DA) and vincristine, prednisone (VP). We reported here this suggestive MPAL case of rare disease condition and effective treatment, in order to provide experience for the early diagnosis and treatment of similar patients. [ABSTRACT FROM AUTHOR]

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) is rare and associated with poor clinical outcome especially in adults. ETP tumor cells that express cross-lineage antigens or lack pan T markers usually pose big challenges to diagnosis, and their prognostic implications are therefore more uncertain. This study reports the unique case of a 44-year-old woman with breast mass as the initial presentation of acute leukemia possessing both T- and B-cell features (cytoplasmic CD3+CD7+CD19+CD79a+). Despite the presence of gene rearrangements of IGH and IGK probably in a small amount of B cells, the patient was diagnosed with T-ALL mainly according to WHO criteria, and further ETP-ALL rather than mixed phenotype ALL based on additional positive expression of stem/myeloid lineage antigens (CD34+CD13+CD33+HLA-DR+). Moreover, in spite of normal karyotype, SET-NUP214 gene fusion is identified, which has not been described in ETP-ALL with bi-phenotype. After intensive chemotherapy, the patient achieved short-term morphologic complete remission but relapsed within one month. This report may expand immunophenotype and clinical behavior of ETP-ALL in adults. Comprehensive evaluations are emphasized in making a differential diagnosis and distinguishing subtypes of acute leukemia. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia where blasts present phenotypes from more than one lineage. A poor prognostic has been associated with this disease, and limited data are currently available to guide the choice of therapy. Regarding FLT3‐positive MPAL, only one case treated with midostaurin has been published to date. Here, we report the successful use of midostaurin to treat three FLT3‐positive MPAL T/myeloid and B/myeloid patients. Midostaurin was successfully added to intensive induction (two patients) and consolidation chemotherapy (three patients) without significant adverse events requiring a dose adjustment or discontinuation. The therapy received resulted in complete remission for two patients and complete remission with an incomplete hematologic recovery for the third. All patients proceeded to HSCT and stayed in remission after an extended follow‐up respectively at 28, 31, and 11 months later. These results suggest that the addition of midostaurin during induction and consolidation therapy may represent a treatment option for FLT3‐positive MPAL. [ABSTRACT FROM AUTHOR]

Acute leukemias of ambiguous lineage (ALAL) are rare hematologic malignancies with poor outcomes. Retrospective studies have suggested that acute lymphoblastic leukemia (ALL) regimens are more effective than acute myeloid leukemia (AML) regimens. We retrospectively examined the effectiveness of the widely-used adult ALL regimen hyperfractionated cyclophosphamide, vincristine, doxorubicin, and dexamethasone (hyperCVAD) as initial therapy in patients with ALAL at five academic institutions. Twenty-five patients were identified, including 23 with mixed phenotype acute leukemia (MPAL) and two with acute undifferentiated leukemia. Five of 8 tested (63%) had FLT3-ITD and 3 of 25 (12%) were Philadelphia chromosome-positive. The complete remission (CR) rate was 76%, with CR with incomplete count recovery (CRi) in an additional 8%, for an overall response rate of 84%. Median number of cycles to CR/CRi was 1. There were no deaths in the first 30 days. Of the 21 patients achieving CR or CRi, 14 (66%) proceeded to allogeneic hematopoietic stem cell transplantation. With a median follow-up time of 31.6 months, median overall survival for the entire cohort was not reached, and the estimated 2-year survival was 63%. HyperCVAD can be considered an effective and tolerable front-line regimen for patients with ALAL, and warrants further prospective study. [ABSTRACT FROM AUTHOR]

Objectives: The aim of this population‐based, retrospective study was to analyze biological and clinical features and treatment results in children diagnosed with MPAL in all Polish pediatric oncology centers between 2007 and 2018. Methods: Among 2893 children and adolescents diagnosed and treated for acute leukemia, 39 (1.35%) patients fulfilled the WHO criteria of MPAL. The T/myeloid phenotype was most prevalent. Results: Cytogenetics findings were seen in 2 (5.1%), while chromosomal abnormalities were found in 14 (35.9%) patients. Thirty‐two patients achieved CR‐1, including 23 (92.0%) treated with ALL‐directed chemotherapy and 9 (64.3%) treated with AML‐type induction regimens. Within these patients, 4 (12.5%) died due to treatment‐related complications and 11 (34.4%) relapsed. Nineteen (63.3%) patients underwent allo‐HSCT in CR‐1 and 14 (73.7%) of them have been in CR‐1. In total, 17 (43.6%) patients remain in CR‐1 for 1‐12 years, including 14 (58.3%) with T/myeloid MPAL. The 5‐year pOS and pEFS were 51.8% and 44.2%, respectively. The overall survival for ALL‐directed therapy was significantly better than the one for AML‐type chemotherapy (P =.001). It was also better for patients who underwent HSCT in CR‐1 (P =.001). Conclusions: The prognosis of MPAL is unsatisfactory, but initial treatment with ALL‐directed chemotherapy consolidated with allo‐HSCT improves the outcomes in MPAL. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndrome (MDS) that evolves into acute leukemia with blasts of mixed phenotypes has rarely been reported and has no distinct diagnostic category. Herein, we describe a 79-year-old Korean female patient with MDS–excess blasts (MDS-EB) that evolved into acute leukemia; the blasts simultaneously expressed B-lymphoid and myeloid antigens. The patient was diagnosed with MDS-EB with blasts of myeloid lineage coexpressing a few B-lymphoid antigens with 7q and 20q abnormalities. The disease progressed to acute leukemia with blasts carrying more B-lymphoid antigens, which was immunophenotypically compatible with B-lymphoid/myeloid acute leukemia. Unlike previously reported patients whose blast populations are bilineal, our patient is the first with biphenotypic acute leukemia that progressed from MDS. The diagnosis of our patient introduces the possibility that many other types of biphenotypic acute leukemia may have gone undiagnosed and encourages hematologists to designate a specific diagnostic category for this type of disease, so that it can more readily be detected and studied in the future. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukaemia (MPAL) is a diverse group of leukemia of ambiguous lineage diagnosed when blasts in peripheral blood and/or bone marrow have antigens of more than one lineage or a mosaic of blasts belonging to more than one lineage. Retrospective analysis of 218 consecutive cases of acute leukaemia diagnosed by multiparametric flow cytometry (FCM) was done. MPAL cases were identified in accordance with European Group for the Immunological Classification of Leukaemias Criteria and World Health Organization 2008/2016 guidelines for lineage assignment. Nine out of 218 (4.1%) cases were classified as MPAL. Eight out of nine patients (88.8%) were male and 4/9 (44.4%) were < 20 years of age. There were three cases of B/T and T/myeloid MPAL each. Two cases were B/myeloid MPAL and one case was chronic myeloid leukaemia (CML) in B/myeloid blast crisis. B/myeloid MPAL and CML in B/myeloid blast crisis cases were Philadelphia chromosome positive. The latter case had a complex karyotype as well. Seven cases were treated with acute lymphoblastic leukaemia treatment regimen; two of them achieved complete remission (CR). The patient with CML in B/myeloid blast crisis was treated with imatinib based regimen, attained CR, underwent allogenic bone marrow stem cell transplantation, but developed graft versus host disease. Five patients died due to complications of febrile neutropenia early in the course of treatment (62.5%). The last patient (B/T MPAL) refused therapy and was lost to follow-up. Early accurate diagnosis of MPAL requires FCM. It may be misdiagnosed if a limited panel of antibodies is used. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is an uncommon diagnosis, representing only about 2-5% of acute leukemia cases. The blast cells of MPAL express multilineage immunophenotypic markers and may have a shared B/T/myeloid phenotype. Due to historical ambiguity in the diagnosis of MPAL, the genetics and clinical features of this disease remain poorly characterized. Based on the 2008 and 2016 World Health Organization classifications, myeloid lineage is best determined by presence of myeloperoxidase, while B and T lymphoid lineages are demonstrated by CD19 and cytoplasmic CD3 expression. MPAL typically carries a worse prognosis than either acute myeloid leukemia (AML) or acute lymphoid leukemia (ALL). Given the rarity of MPAL, there is a lack of prospective trial data to guide therapy; treatment generally relies on ALL-like regimens followed by consolidation chemotherapy or hematopoietic stem cell transplant (HSCT). Here, we review the updated classification, biology, clinical features, and treatment approach to MPAL. [ABSTRACT FROM AUTHOR]

Objective: To evaluate Immunophenotyping patterns in Mixed-Phenotype Acute Leukemias (MPAL). Study Design: Descriptive study. Place and Duration of Study: This study was carried out in the department of Hematology, Armed Forces Institute of Pathology Rawalpindi, from 1st Jan 2013 to 31st Jan 2017. Material and Methods: After taking informed consent from the patients fulfilling the inclusion criteria, detailed history was taken and blood samples were drawn for blood complete picture. The patients suspected to have acute leukemia were subjected to bone marrow examination (aspiration and trephine biopsy) for further cytochemical staining (SBB) and Immunophenotyping. Results: Total 680 new cases of acute leukemias on initial workup of either gender age were included. Patients of other haematological disorders were excluded from the study. Among 680 new cases of acute leukaemia, 23(3.4%) cases were of MPAL immunophenotyping using scoring system proposed by EGIL (European Group for the Immunological Characterization of Leukemias) classification. Among MPAL, 19(83%) cases were Biphenotypic [13(57%) cases of My/B-ALL, 5(22%) cases of My/T-ALL, and 1(4%) case of T/B-ALL]. 4(17%) cases were Bilineage (My/B-ALL). Most of the cases were diagnosed at less than 10 years of age. Conclusion: My/B-ALL is the most common immunophenotype followed by My/T-ALL. Therefore immunophenotyping is indispensable for diagnosis and for therapy decisions of MPAL. [ABSTRACT FROM AUTHOR]

Histoplasmosis has been observed in patients with immunosuppression in the form of isolated pulmonary involvement and disseminated disease. However, very few cases of this type that involved pleural effusion have been reported, and none have been reported in a case individual with mixed-phenotype acute leukemia (MPAL). Herein, we report a case involving a 23 year old Punjabi man having fever and breathlessness in the postinduction therapy period for mixed-phenotype acute leukemia (MPAL) with diagnosis of histoplasmosis based on the results of pleural fluid cytologic testing. The diagnosis of histoplasmosis may be missed in routine pleural fluid cytology testing; however, a high degree of suspicion for opportunistic infections in patients with immunocompromised state can aid diagnosis. [ABSTRACT FROM AUTHOR]

Mixed phenotype acute leukemia (MPAL) is a rare hematolymphoid neoplasm, representing only 3%-5% of acute leukemia. Although MPAL has been sufficiently described in the literature, its extramedullary presentation as a solitary lesion without leukemic (bone marrow [BM]) involvement is rarely described. We are presenting two cases of mixed phenotypic blastic hematolymphoid neoplasms without leukemic involvement at disease presentation in 8-year-old female and 21-year-old male patients. Both the cases had extralymphatic bone involvement in the form of solitary bone lesion. Initially, there was no leukemic involvement in both the cases, but the second case progressed to acute leukemia during the course of the disease. On immunophenotypic evaluation, both the cases revealed blasts showing unequivocal evidence of myeloid and B-lymphoid lineage commitment. These cases were difficult to categorize either into MPAL as the BM was not involved or into lymphoblastic lymphoma due to coexpression of myeloid differentiation. Therefore, we chose to classify them as a bi/mixed phenotypic blastic hematolymphoid neoplasm. Detailed immunophenotypic analysis either by immunohistochemistry or flow cytometric immunophenotyping is important for the diagnosis of such cases as they have a poor prognosis. [ABSTRACT FROM AUTHOR]

Key Clinical Message Mixed phenotype acute leukemia with t(9;22) is a rare disease with poor prognosis, and information on optimal treatment is limited. We describe a case where our patient experienced positive outcome after nonacute myeloid leukemia-type intensive induction therapy followed by postremission therapy with stem cell transplant. [ABSTRACT FROM AUTHOR]

The t(12; 17)(p13;q11 ~ 21) translocation is a very rare but recurrent cytogenetic aberration observed predominantly in early pre-B acute lymphoblastic leukemia (ALL) with CD19+CD10-CD33+ phenotype. This translocation was shown to form a fusion gene between TAF15 at 17q12 and ZNF384 at 12p13. On the other hand, der(1; 18)(q10;q10) has been detected as a rare unbalanced whole-arm translocation leading to trisomy 1q in myeloid malignancies. We describe here the first case of mixed phenotype acute leukemia (MPAL) with a t(12; 17)(p13;q21)/ TAF15-ZNF384, which also had der(1; 18)(q10;q10) as an additional abnormality. A 74-year-old woman was diagnosed with MPAL, B/myeloid, because bone marrow blasts were positive for myeloperoxidase, CD19, and CD22. Chromosome analysis showed 46,XX, +1,der(1;18)(q10;q10),t(2;16)(q13;q13),t(12;17)(p13;q21). Expression of the TAF15-ZNF384 fusion transcript was confirmed: TAF15 exon 6 was fused in-frame to ZNF384 exon 3. This type of fusion gene has been reported in 1 acute myeloid leukemia case and 3 ALL cases. Thus, at present, it is difficult to find a specific association between the structure of the TAF15-ZNF384 fusion gene and the leukemia phenotype. The TAF15-ZNF384 fusion may occur in early common progenitor cells that could differentiate into both the myeloid and lymphoid lineages. Furthermore, der(1; 18) (q10;q10) might play some role in the appearance of an additional myeloid phenotype. [ABSTRACT FROM AUTHOR]

We report a case of Cyberlindnera fabianii fungemia after umbilical cord blood transplantation (CBT). A 69-year-old woman was diagnosed as having mixed phenotype acute leukemia. The patient received CBT for primary refractory disease. After preconditioning chemotherapy, the patient's condition deteriorated, leading to acute respiratory failure from capillary leak syndrome and consequent admittance to the intensive care unit. The patient recovered temporarily following the administration of noninvasive positive pressure ventilation and continuous hemodiafiltration, but died of fungemia with the presence of yeast-like cells 15 days post-CBT. The yeast-like cells were analyzed by sequencing of the D1/D2 domain of the large subunit and the internal transcribed spacer domain, and were identified as C. fabianii. This case shows that molecular genetic-based methods may be effective for detecting undetermined invasive fungal infections in stem cell transplantation settings. [ABSTRACT FROM AUTHOR]

Adult patients with mixed phenotype acute leukemia ( MPAL) have a poor prognosis, and the therapeutic role of allogeneic stem cell transplantation (allo- SCT) for MPAL remains to be elucidated. Thus, we retrospectively assessed the efficacy of allo- SCT for MPAL. Eighteen patients with MPAL were identified from the transplant outcome database of Kanto Study Group for Cell Therapy ( KSGCT). We also selected 215 patients with acute myeloid leukemia ( AML) and acute lymphoblastic leukemia ( ALL) as control cohorts using an optimal matching method. The 5-yr overall survival ( OS) rate of patients with MPAL was 48.1%, and patients in remission at the time of transplant showed significantly better survival than those not in remission (5-yr OS: 71.8% vs. 0%, P = 0.001). No significant differences were seen in OS when stratifying patients according to immunophenotype, cytogenetic abnormalities, or the type of induction therapy. The 5-yr OS rate of patients with MPAL was not significantly different compared with AML control patients (48.1% vs. 48.1%; P = 0.855) or ALL control patients (48.1% vs. 37.8%; P = 0.426). These results suggested that allo- SCT is an effective treatment for MPAL, especially early in the disease course, and innovative transplant approaches are warranted to improve the transplant outcome of patients with MPAL who are not in remission. [ABSTRACT FROM AUTHOR]

Objectives: This session of the Society for Hematopathology/ European Association for Haematopathology Workshop focused on acute leukemias of ambiguous origin. Methods: We provide an overview of mixed-phenotype acute leukemia (MPAL) as recognized in the current World Health Organization classification and summarize diagnostic criteria for major categories of MPAL: B/myeloid, T/myeloid, B/T, and B/T/myeloid. Results: Most MPAL cases submitted were B/myeloid and T/myeloid MPAL, the most frequent types, but three cases of B/T MPAL were also submitted, and examples of all categories are illustrated. We emphasize that a comprehensive approach to immunophenotyping is required to accurately establish the diagnosis of MPAL. Flow cytometry immunophenotyping using a large panel of antibodies is needed as well as confirmatory immunohistochemical analysis and cytochemistry studies for myeloperoxidase and nonspecific esterase. We discuss technical issues in determining blast lineage and possible pitfalls in MPAL diagnosis. In particular, rare cases of B-acute lymphoblastic leukemia (B-ALL) can express myeloperoxidase but are otherwise consistent with B-ALL and should be treated as such. Last, we review the differential diagnosis between acute undifferentiated leukemia and acute myeloid leukemia with minimal differentiation. Conclusions: There was an agreement that diagnosis of MPAL can be challenging, especially if applied flow cytometry panels are not comprehensive enough. [ABSTRACT FROM AUTHOR]

Background Mixed phenotype acute leukemias (MPAL) include acute leukemias with blasts that express antigens of more than one lineage, with no clear evidence of myeloid or lymphoid lineage differentiation. T/myeloid (T/My) MPAL not otherwise specified (NOS) is a rare leukemia that expresses both T and myeloid antigens, accounting for less than 1% of all leukemias but 89% of T/My MPAL. From a molecular point of view, very limited data are available on T/My MPAL NOS. Case presentation In this report we describe a T/My MPAL NOS case with a complex rearrangement involving chromosomes 5 and 14, resulting in overexpression of the ADAM metallopeptidase with thrombospondin type 1 motif, 2 (ADAMTS2) gene due to its juxtaposition to the T cell receptor delta (TRD) gene segment. Conclusion Detailed molecular cytogenetic characterization of the complex rearrangement in the reported T/My MPAL case allowed us to observe ADAMTS2 gene overexpression, identifying a molecular marker that may be useful for monitoring minimal residual disease. To our knowledge, this is the first evidence of gene dysregulation due to a chromosomal rearrangement in T/My MPAL NOS. [ABSTRACT FROM AUTHOR]

Objectives: The 2008 World Health Organization (WHO) classification system grouped bilineal and biphenotypic acute leukemias together under a new heading of mixed phenotype acute leukemia (MPAL). The lineage-specific marker criteria have also changed for a diagnosis of MPAL. The goal of this study was to characterize clinical significance of this new group. Methods: Sixty-one patients diagnosed with MPAL using either European Group for the Immunological Classification of Leukaemias (EGIL) criteria or 2008 WHO criteria were included in this study. Results: Sixteen patients (26%) diagnosed with acute biphenotypic leukemia using EGIL criteria did not fulfill 2008 WHO criteria for MPAL. Cytogenetic data were available for 32 patients, and the most common abnormality was t(9;22) (five of 32 cases). Clinical outcome data suggested that younger patients with MPAL (≤21 years) had better overall survival (OS) in both the EGIL and WHO groups (EGIL, P = .0403; WHO, P = .0601). Compared with 177 patients with acute myeloid leukemia (AML), MPAL patients had better OS (P = .0003) and progression-free survival (P = .0001). However, no difference in OS between MPAL and 387 patients with acute lymphoblastic leukemia was present (P = .599). Conclusions: As defined by the 2008 WHO classification, fewer patients are now classified as having MPAL than with the EGIL criteria. In this study, patients with MPAL have a better clinical outcome compared with patients with AML. [ABSTRACT FROM AUTHOR]

Although the introduction of imatinib dramatically improved the outcomes for patients with Philadelphia chromosome-positive B-cell precursor acute lymphoblastic leukemia ( Ph+ BCP- ALL), the survival benefit of imatinib has not been assessed in the context of Ph+ mixed phenotype acute leukemia ( Ph+ MPAL). To clarify this important issue, we studied 42 Ph+ acute leukemia ( Ph+ AL) patients who received intensive chemotherapy and concurrent administration of imatinib. Of the 42 Ph+ AL patients, 13 (31%) patients were categorized as Ph+ MPAL (positive for both myeloid and B-cell lineage), 27 (64%) were categorized as Ph+ BCP- ALL, and two (5%) were categorized as Ph+ acute myeloid leukemia. The complete remission rates after the initial induction therapy were not significantly different when comparing Ph+ MPAL and Ph+ BCP- ALL patients (100% vs. 85%, respectively, P = 0.14). Likewise, there were no significant differences in the 5-yr overall survival ( OS) or disease-free survival ( DFS) rates when comparing the MPAL and BCP- ALL groups ( OS: 55% vs. 53%, respectively, P = 0.87, DFS: 46% vs. 42%, respectively, P = 0.94). These findings suggest that concurrent imatinib administration with chemotherapy improved the outcomes of Ph+ MPAL patients to the level seen in Ph+ BCP- ALL patients and should, therefore, be considered as the standard therapy for these patients. [ABSTRACT FROM AUTHOR]

Background Mixed phenotype acute leukemia (MPAL) is a rare hematological malignancy characterized by combinatorial aberrations involving cells of the myeloid, T-, and/or B- lineages, most often diagnosed by means of immunophenotyping in order to assess lineage-specific markers, which can still yield inconclusive diagnoses. MPAL with a complex karyotype (three or more chromosomal abnormalities) is a cytogenetic subtype of MPAL associated with a poor prognosis, but limited data is available about the cytogenetic abnormalities present in this context. Findings Herein, we present the case of a 67-year-old female whose bone marrow biopsy revealed an extensive blast population showing dual morphologic differentiation, including lymphoblasts and larger myeloblasts with monocytic differentiation. Multiparametric immunophenotyping by flow cytometry revealed a blast population that was positive for CD45, CD19, CD22, CD34, CD38, and HLA-DR. The blast populations were also immunereactive for both myeloperoxidase and TdT; thus, a diagnosis of mixed phenotype acute leukemia was rendered. Conventional cytogenetic analysis revealed a hyperdiploid composite karyotype with numerical abnormalities involving chromosomes 2, 6, 8, 10, 11, 14, 19, 20, 21, and 22, as well as structural abnormalities involving 1p, 1q, 9p, 16p, 17p, 19q, 20q, and a marker chromosome. Concurrent interphase and metaphase FISH studies were able to detect a deletion of CDKN2A/p16 at 9p21 and corroborated the presence of extra copies of chromosomes 8, 11, 20, and 22. Conclusions This case provides further insight into the plethora of cytogenetic abnormalities not involving BCR-ABL1 and/or MLL present in MPAL with a complex karyotype and adds to the pool of cytogenetic information about this rare subset of hematological malignancies. [ABSTRACT FROM AUTHOR]

Philadelphia chromosome-positive mixed phenotype acute leukemia (PhMPAL) is a rare type of acute leukemia having myeloid and lymphoid features. In the present study, we describe the successful treatment of a 71-year-old Japanese female patient with PhMPAL by the alternation of second-generation tyrosine kinase inhibitors according to BCR-ABL1 mutations. The patient survived in her third complete remission (CR) for over 4 years. In her first CR, the patient was treated with multiple-agent chemotherapy and underwent maintenance therapy with imatinib and monthly vincristine and prednisolone (VP). At the first relapse, an examination of the bone marrow revealed a transformation into acute lymphoblastic leukemia and an F317L mutation in BCR-ABL1 gene, which responded preferentially to nilotinib over dasatinib. She achieved second CR, and nilotinib with VP therapy was selected for maintenance treatment. At second relapse, BCR-ABL1 mutational analysis revealed Y253H mutation instead of F317L mutation, resulting in resistance to nilotinib. The patient achieved third CR with dasatinib and VP therapy, and maintained CR with this treatment. This suggests that appropriate alternation of TKIs may contribute to long-term survival in elderly patients with PhMPAL. [ABSTRACT FROM AUTHOR]