Acute bilineal leukemia: a rare disease with poor outcome

Acute leukemia of ambiguous lineage: Diagnosis, prognosis and treatment

Acute leukemias of ambiguous lineage (ALAL) are an infrequent subtype of acute leukemias without clear evidence of differentiation to a one single cell lineage. Despite their rarity constitute a recognized subgroup in the recent international classifications, such as the WHO (World Health Organization) classification. Their diagnosis require highly specialized flow cytometry technology, and also cytogenetics and molecular techniques. The low frequency of the disease has made it difficult to find the best therapeutic strategy, due both to the lack of prospective studies and randomized trials, and to the heterogeneity of the published retrospective studies on follow-up and treatment. The group of ALAL has bad prognosis, and usually requires intensive strategies that include consolidation with allogeneic stem cell transplant as part of the treatment. The objective of this review was to analyze diagnosis, treatment and prognosis of this rare subtype of leukemias.

A Rare Case of Therapy-Related B-cell Acute Lymphoblastic Leukemia Arising From Acute Myeloid Leukemia

Therapy-related acute lymphoblastic leukemia (t-ALL) is a rare potential complication of chemotherapy. We describe the case of a 47-year-old male patient who was originally diagnosed with t(8;21) positive acute myeloid leukemia (AML) in 2019, received chemotherapy, achieved remission, and was disease-free for the next two years. During a routine follow-up in 2022, he was found to have developed subclinical pancytopenia, and further studies indicated a diagnosis of pH-negative, near-tetraploid B-cell acute lymphoblastic leukemia (B-ALL) that was positive for a Tier 1 TP53 mutation, consistent with t-ALL. The patient had a prolonged treatment course complicated by social factors, such as the impact of both disease and treatment on his ability to work enough to make a living and live life with the quality he desired. The patient elected to pause treatment and resume it at a later date, after which, unfortunately, significant disease progression occurred and the patient died from complicating neutropenic sepsis and variceal bleeding. This case illustrates the challenges of managing social circumstances and patient goals in the setting of medically necessary but potentially harsh treatment courses. Given the aggressive nature of t-ALL and its overall poor prognosis, goals of care must be re-evaluated and discussed often to ensure alignment of therapy with a patient's wishes.

Multicenter retrospective analysis of clinical outcome of adult patients with mixed-phenotype acute leukemia treated with acute myeloid leukemia-like or acute lymphoblastic leukemia-like chemotherapy and impact of allogeneic stem cell transplantation: a Campus ALL study

Mixed-phenotype acute leukemia (MPAL) is a rare disease. Treatment is often similar to that of acute lymphoblastic leukemia (ALL), but the outcome in adults and the role of allogeneic stem cell transplantation (AlloSCT) are not well defined. We report on 77 adult patients diagnosed with MPAL over the last 10 years and treated with a curative intent. Median age was 49 years; 7.6% of cases had a BCR::ABL1 rearrangement. Thirty patients (39%) were treated with an acute myeloid leukemia (AML)-like induction and 47 (61%) with an ALL-like scheme. The complete remission (CR) rate was 67.6% and an ALL-like therapy was associated with a better CR rate (P = 0.048). The median OS was 41.9 months; age ≤ 60 years was associated with a better OS (67 vs 26 months, P = 0.014). An AlloSCT was performed in 50 patients (65%). The 5-year OS of transplanted patients was 54%. The OS post-AlloSCT was better in patients who were minimal residual disease (MRD)-negative prior to transplant (75.8% vs 45.2%, P = 0.06). This study shows that MPAL patients respond better to an ALL-like induction therapy; that consolidation therapy should include, whenever possible, an AlloSCT and that MRD negativity should be a primary endpoint of treatment.

Recognizing Minor Leukemic Populations with Monocytic Features in Mixed-Phenotype Acute Leukemia by Flow Cell Sorting Followed by Cytogenetic and Molecular Studies: Report of Five Exemplary Cases

Mixed-phenotype acute leukemia (MPAL), a rare and heterogeneous category of acute leukemia, is characterized by cross-lineage antigen expression. Leukemic blasts in MPAL can be represented either by one population with multiple markers of different lineages or by several single-lineage populations. In some cases, a major blast population may coexist with a smaller population that has minor immunophenotypic abnormalities and may be missed even by an experienced pathologist. To avoid misdiagnosis, we suggest sorting doubtful populations and leukemic blasts and searching for similar genetic aberrations. Using this approach, we examined questionable monocytic populations in five patients with dominant leukemic populations of B-lymphoblastic origin. Cell populations were isolated either for fluorescence in situ hybridization or for clonality assessment by multiplex PCR or next-generation sequencing. In all cases, monocytic cells shared the same gene rearrangements with dominant leukemic populations, unequivocally confirming the same leukemic origin. This approach is able to identify implicit cases of MPAL and therefore leads to the necessary clinical management for patients.

Single-cell analysis of acute lymphoblastic and lineage-ambiguous leukemia: approaches and molecular insights

Despite recent progress in identifying the genetic drivers of acute lymphoblastic leukemia (ALL), prognosis remains poor for those individuals who experience disease recurrence. Moreover, acute leukemias of ambiguous lineage lack a biologically informed framework to guide classification and therapy. These needs have driven the adoption of multiple complementary single-cell sequencing approaches to explore key issues in the biology of these leukemias, including cell of origin, developmental hierarchy and ontogeny, and the molecular heterogeneity driving pathogenesis, progression, and therapeutic responsiveness. There are multiple single-cell techniques for profiling a specific modality, including RNA, DNA, chromatin accessibility and methylation; and an expanding range of approaches for simultaneous analysis of multiple modalities. Single-cell sequencing approaches have also enabled characterization of cell-intrinsic and -extrinsic features of ALL biology. In this review we describe these approaches and highlight the extensive heterogeneity that underpins ALL gene expression, cellular differentiation, and clonal architecture throughout disease pathogenesis and treatment resistance. In addition, we discuss the importance of the dynamic interactions that occur between leukemia cells and the nonleukemia microenvironment. We discuss potential opportunities and limitations of single-cell sequencing for the study of ALL biology and treatment responsiveness.

Characteristics, Treatment Complexity, and Outcome of Mixed-Phenotype Acute Leukemia in Children in a Low–Middle-Income Country

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.

Hypocellular Philadelphia chromosome-positive mixed-phenotype acute leukemia successfully treated with dasatinib: A case report

Both hypocellular leukemia and Philadelphia (Ph) chromosome-positive mixed-phenotype acute leukemia (MPAL) are rare subtypes of leukemia showing unfavorable outcomes and lacking established optimal management. Ph-positive leukemia most often presents with hypercellularity and hypoplasia is a rare condition. The present study reports an extremely rare case of hypocellular biclonal Ph-positive MPAL, which was diagnosed by biopsy and genetic analysis of bone marrow, and successfully treated with dasatinib and steroids. Briefly, a 77-year-old man presented with pancytopenia and flow cytometry of bone marrow could not be evaluated due to hypocellularity. The patient was finally diagnosed with hypocellular Ph-positive MPAL by genetic analysis and immunostaining of bone marrow biopsy. Although blood cells recovered with methylprednisolone pulse administration alone for concurrent optic neuritis, hematopoietic function rapidly normalized with dasatinib administered after definitive diagnosis of Ph-positive leukemia. Dasatinib and oral prednisolone were continued following methylprednisolone pulse administration and the patient achieved molecular complete remission (CR) on day 140 of treatment; molecular CR was maintained thereafter without any severe adverse events. In conclusion, the combination of dasatinib and a steroid may be one of the tolerable treatment options for elderly patients with hypocellular biclonal Ph-positive MPAL. Furthermore, genetic analysis and immunostaining of bone marrow biopsy can help with the diagnosis of leukemia with hypocellular bone marrow.

Pediatric Mixed-Phenotype Acute Leukemia: What's New?

Simple Summary

Pediatric mixed-phenotype leukemia is a rare form of blood cancer in children. In this review, we cover both the evolution of treatment over the past several years and outline new emerging concepts in this disease.

Abstract

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.

Update on Acute Leukemias of Ambiguous Lineage

Acute leukemias of ambiguous lineage are a heterogenous group of diseases that include acute undifferentiated leukemias and mixed-phenotype acute leukemias (MPALs). These leukemias pose a challenge for pathologists and clinicians alike in diagnosis, treatment, and further management. Recent genetic characterization has provided insights into their underlying biology and classification, and has offered potential for targeted therapies. This article addresses diagnosis of MPALs with examples of the most common pitfalls, recent comprehensive molecular studies, and advancement in treatment and follow-up modalities.

Diagnosis of rare subtypes of acute myeloid leukaemia and related neoplasms

The diagnosis of acute myeloid leukaemia and related neoplasms in adults is challenging as this requires the integration of clinical findings, morphology, immunophenotype, cytogenetics, and molecular genetic findings. Lack of familiarity with rare subtypes of acute leukaemia hinders the diagnosis. In this review, we will describe diagnostic findings of several rare acute myeloid leukaemias and related neoplasms that primarily occur in adults including information on presentation, morphology, immunophenotype, genetics, differential diagnosis, and prognosis. Leukaemias discussed include blastic plasmacytoid dendritic cell neoplasm, acute myeloid leukaemia with t(6;9) (p23;q34.1); DEK-NUP214, acute myeloid leukaemia with inv(3)(q21.3q26.2) or t(3;3)(q21.3;q26.2); GATA2, MECOM, acute myeloid leukaemia with BCR-ABL1, acute leukaemias of ambiguous lineage, acute myeloid leukaemia with mutated RUNX1, pure erythroid leukaemia, acute panmyelosis with myelofibrosis, and acute basophilic leukaemia. Case studies with morphological features of the nine subtypes of acute myeloid leukaemia and related neoplasms have been included, and additional evidence available since publication of the 2016 World Health Organization Classification has been added to each subtype.

Early T-Cell Precursor Acute Lymphoblastic Leukemia and T/Myeloid Mixed Phenotype Acute Leukemia Possess Overlapping Characteristics and Both Benefit From CAG-Like Regimens and Allogeneic Hematopoietic Stem Cell Transplantation

Early T-cell precursor acute lymphoblastic leukemia (ETP-ALL) and T-lymphoid/myeloid mixed phenotype acute leukemia (T/M-MPAL) are closely related entities and remain a therapeutic challenge. In this study, we characterized the clinical features of 43 ETP-ALL and 41 T/M-MPAL patients and compared clinical outcomes and safety between cytarabine, aclarubicin, and granulocyte colony-stimulating factor (CAG)-like regimens in 34 patients and conventional ALL regimens in 50 patients. In our series, ETP-ALL and T/M-MPAL showed similar biological characteristics, immunophenotypes, genomic alterations, and outcomes. The complete remission (CR) rate and minimal residual disease (MRD)-negative CR rate of CAG-like regimens were significantly higher compared with conventional ALL regimens (CAG-like: 80.0% and 59.7%, respectively; P = .039; ALL: 51.4% and 31.3%, respectively; P = .048). Overall, 90.0% of cases (18/20) achieved CR using combined decitabine and CAG-like regimens. Additionally, CAG-like regimens had lower rates of grade 3 or 4 infection (18.8% vs. 38.2%; P = .059) and grade 1 or 2 hepatotoxicity (37.5% vs. 60.0%; P = .043) than conventional ALL regimens. The 38 patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT) in the first CR (CR1) had better overall survival (OS) and leukemia-free survival (LFS) than the 11 patients who underwent allo-HSCT in the second CR (CR2) or in no remission (median OS not reached vs. 7.6 months, P = .0004; median LFS not reached vs. 11.6 months, P = .0008). There was a significant difference in 3-year OS (95.7% vs. 52.5%; P = .0039) and LFS (95.8% vs. 43.5%; P = .0003) after allo-HSCT between pre-transplant MRD-negative and MRD-positive patients. The median OS for patients without allo-HSCT was 32.1 months in the CAG-like group compared with 12.1 months in the non-CAG-like group (P = .019). These findings suggest that ETP-ALL and T/M-MPAL possess overlapping characteristics and CAG-like regimens improve their clinical outcomes.

Mixed Phenotype Acute Leukemia: Current Approaches to Diagnosis and Treatment

PURPOSE OF REVIEW

Mixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia with features of both acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). The review examines current definitions and controversies in classification of MPAL, new insights into genomic drivers and pathogenesis, recent evidence to support treatment recommendations, and opportunities for future research.

RECENT FINDINGS

Recent collaborative efforts have made progress in understanding the genomic landscape and optimal therapy for MPAL. The preponderance of retrospective data supports beginning therapy with ALL directed regimens. Differences in prognosis for adult and children with MPAL have led to divergent approaches for therapy intensity, including use of stem cell transplantation consolidation. MPAL remains a challenging leukemia to understand, research, and treat due to low incidence, shifting and subjective approaches to classification, and innate biological heterogeneity. Ongoing research hopes to surmount these obstacles through prospective studies within large cooperative groups to provide new insight into targetable biology and further refine optimal therapy.

Clinicoepidemiologic Profile and Outcome Predicted by Minimal Residual Disease in Children With Mixed-phenotype Acute Leukemia Treated on a Modified MCP-841 Protocol at a Tertiary Cancer Institute in India

INTRODUCTION

Mixed-phenotype acute leukemia (MPAL) accounts for 1.2% to 5% of acute leukemia across age groups with intermediate prognosis. We evaluated clinicoepidemiologic profiles and outcomes of MPAL.

METHODS

Records of children younger than 15 years of age with acute leukemia from January 2010 to December 2016 were reviewed on the basis of the MPAL WHO 2008 criteria. Treatment was uniform with a modified MCP-841 protocol. Descriptive analysis tools were used. Outcomes were measured by the Kaplan-Meier method on MedCalc, version 14.8.1.

RESULTS

Among 3830 children with acute leukemia in the study period, 2892 received treatment from our center, of whom 24 (0.83%) had MPAL, median age 9 years, with a male:female ratio of 3:1, and median white blood cell of 13.4×10/L. Common immunophenotypes were B/myeloid-12 (50%), T/myeloid-9 (37.5%), and B/T-lymphoid-3 (12.5%). Some B/myeloid cases had abnormal cytogenetics. Seventeen patients were evaluable for outcome. Sixteen patients underwent postinduction bone marrow and 13 (81%) achieved morphologic remission. Thirteen patients underwent flow cytometry-based minimal residual disease evaluation; 9 (69%) were <0.01% (4 postinduction, 5 postconsolidation), and 67% of these had sustained remission till the last follow-up. None underwent bone marrow transplant. The projected 3-year event-free and overall survival rates were 40% and 48%, respectively (median follow-up: 22 mo).

CONCLUSION

MPAL represented <1% of childhood acute leukemia. acute lymphoblastic leukemia-type chemotherapy that incorporated high-dose cytarabine was effective in achieving an minimal residual disease-negativity rate of 69% in evaluated patients, which was also predictive of better outcome.

Concomitant use of blinatumomab and donor lymphocyte infusion for mixed-phenotype acute leukemia: a case report with literature review

Blinatumomab and donor lymphocyte infusion (DLI) combination is a promising cancer therapy, whereby blinatumomab might achieve an initial reduction in leukemic-cell burden using T cells, and after tumor clearance, DLI can potentially stimulate the donor immune system to achieve longer lasting remission. Here, we present a 51-year-old female with mixed phenotype acute leukemia who had a hematologic relapse 3 months after she received total body irradiation-based myeloablative allogeneic hematopoietic stem cell transplantation from an unrelated human leukocyte antigen matched (10/10) donor and achieved complete remission with minimal residual disease negativity by multi-parameter flow cytometry using the combination of blinatumomab and DLI. To the best of our knowledge, this is the first report to describe the use of blinatumomab and DLI combination therapy in the treatment of B/myeloid mixed phenotype acute leukemia.

Acute Leukemias of Ambiguous Lineage: Clarification on Lineage Specificity

Acute leukemias of ambiguous lineage (ALAL) include acute undifferentiated leukemia and mixed-phenotype acute leukemia (MPAL). This article provides an overview of the diagnosis of ALAL and focuses on the data accounting for the current lineage-assignment criteria for blasts harboring more than one lineage-associated marker. In addition, the currently known molecular data are reviewed, which show that MPAL-associated gene mutations, methylation signatures, and expression profiles are a mixture of those seen in both acute myeloid leukemia and acute lymphoblastic leukemia. Finally, the prognosis and current treatments of MPAL are briefly discussed.

Clonal Evolution of B-Cell Acute Lymphoblastic Leukemia with del(9)(p13p21) into Mixed Phenotype Acute Leukemia Presenting as an Isolated Testicular Relapse

Lineage switch in acute leukemias is a well-reported occurrence; however, most of these cases involve a switch from either lymphoid to myeloid or myeloid to lymphoid lineage. Here, we report a case of a 14-year-old male with B-cell acute lymphoblastic leukemia (B-ALL) who initially responded well to standard chemotherapy but then later developed mixed phenotype acute leukemia (MPAL) at relapse, likely reflecting a clonal evolution of the original leukemia with a partial phenotypic shift. The patient had a del(9)(p13p21) in his leukemia blasts at diagnosis, and the deletion persisted at relapse along with multiple additional cytogenetic aberrations. Interestingly, the patient presented with an isolated testicular lesion at relapse, which on further analysis revealed both a lymphoid and myeloid component. Unfortunately, the patient did not respond well to treatment at relapse and eventually succumbed to his disease. To our knowledge, an isolated extramedullary MPAL at relapse in a patient with previously diagnosed B-ALL has not been reported in the literature before.

Multiparametric Flow Cytometry in Mixed Phenotype Acute Leukemia

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.

Aberrant Wnt Signaling Pathway in the Hematopoietic Stem/Progenitor Compartment in Experimental Leukemic Animal

The evolutionarily conserved Wnt signaling pathway regulates physiological hematopoiesis, a process of formation of blood cells and has been shown to play crucial role in the development of both myeloid and lymphoid malignancies. The Wnt signaling pathway can be broadly divided into canonical and non-canonical pathways. In the present study, we investigated the pathobiology of leukemia by studying the expression profile of Wnt proteins, receptors, key signaling intermediates and endogenous Wnt antagonist involved in canonical and non-canonical pathways in the bone marrow (BM) hematopoietic stem/progenitor cell (HSPC) compartment of experimental leukemic mice. Cell adhesion molecule N-Cadherin and leukemic BM microenvironment with reference to Wnt were also studied. We used ENU, a potent carcinogen, to induce leukemia in wild type Swiss albino mice and malignant transformation was cofirmed by peripheral blood and BM studies. Flow cytometric expression analysis revealed profound up-regulation of canonical Wnt3a/β-catenin/CyclinD1 signaling axis along with N-Cadherin whereas down-regulation of non-canonical Wnt5a/Ca2+/CaMKII signaling axis in the leukemic HSPC compartment. Subsequent use of anti-Wnt3a antibody in the in vitro clonogenicity assay uncovered that anti-Wnt3a antibody preferentially inhibited the growth and number of the primitive leukemic hematopoietic CFU-GEMM and BFU-E colonies. Stromal cells derived from the leukemic BM also exhibited aberrant Wnt3a and Wnt5a protein expression. Taken together, alteration of canonical and non-canonical Wnt signaling pathways in the HSPC compartment along with classical Wnt protein expression pattern in the leukemic stromal microenvironment resulted in progression of leukemia.

Non-leukemic pediatric mixed phenotype acute leukemia/lymphoma: Genomic characterization and clinical outcome in a prospective trial for pediatric lymphoblastic lymphoma

Rare cases of hematological precursor neoplasms fulfill the diagnostic criteria of mixed phenotype acute leukemia (MPAL), characterized by expression patterns of at least two hematopoietic lineages, for which a highly aggressive behavior was reported. We present a series of 11 pediatric non-leukemic MPAL identified among 146 precursor lymphoblastic lymphomas included in the prospective trial Euro-LBL 02. Paraffin-embedded biopsies of 10 cases were suitable for molecular analyses using OncoScan assay (n = 7), fluorescence in situ hybridization (FISH; n = 7) or both (n = 5). Except for one case with biallelic KMT2A (MLL) breaks, all cases analyzed by FISH lacked the most common translocations defining molecular subsets of lymphoblastic leukemia/lymphomas. Two non-leukemic B-myeloid MPALs showed the typical genomic profile of hyperdiploid precursor B-cell lymphoblastic leukemia with gains of chromosomes 4, 6, 10, 14, 18, and 21. One B-T MPAL showed typical aberrations of T-cell lymphoblastic lymphoma, such as copy number neutral loss of heterozygosity (CNN-LOH) at 9p targeting a 9p21.3 deletion of CDKN2A and 11q12.2-qter affecting the ATM gene. ATM was also mutated in a T-myeloid MPAL case with additional loss at 7q21.2-q36.3 and mutation of NRAS, two alterations common in myeloid disorders. No recurrent regions of CNN-LOH were observed. The outcome under treatment was good with all patients being alive in first complete remission after treatment according to a protocol for precursor lymphoblastic lymphoma (follow-up 3-10 years, median: 4.9 years). In summary, the present series of non-leukemic MPALs widely lacked recurrently reported translocations in lymphoid/myeloid neoplasias and showed heterogeneous spectrum of chromosomal imbalances.

An update on classification, genetics, and clinical approach to mixed phenotype acute leukemia (MPAL)

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.

Aleukemic extramedullary T lymphoid/myeloid bilineage hematopoietic and lymphoid malignancy with progression to bilineage leukemia at relapse: A case report

Bilineage T lymphoid and myeloid (T/My) neoplasms are rare entities among the hematopoietic and lymphoid malignancies. The majority of patients present with leukemic symptoms in which blasts are observed in the peripheral blood (PB) or bone marrow (BM) at a percentage of >20% of nucleated cells. Only a minimal number of cases of T/My bilineage hematopoietic and lymphoid malignancy have been reported with extramedullary infiltration as the initial symptom. The origin of the neoplastic cells in T/My bilineage malignancy has been documented as the hematopoietic stem cells. The present study reports the case of a 31-year-old man with a T/My bilineage malignancy, which initially showed cervical lymph node enlargement beyond the diagnostic criteria of leukemia in the PB and in the BM. Two distinct malignant populations were detected in the cervical lymph node and pleural effusion, one of which was positive for MPO-staining, while the other was positive for cytoplasmic cluster of differentiation 3. Mutations in platelet-derived growth factor receptor α, platelet-derived growth factor receptor β, fibroblast growth factor receptor 1 and other chromosome abnormalities were excluded. The patient obtained complete remission after conventional chemotherapy, but relapsed with bilineage leukemia within a short period of time. Lymphoid and myeloid lineages have been reported to be differentiated from multipotent progenitors asymmetrically. However, the cellular mutation stage in T/My bilineage malignancy remains unclear. The present study also reviews the origin, development and therapeutic strategies for extramedullary T/My bilineage malignancy.

Mixed phenotype acute leukemia contains heterogeneous genetic mutations by next-generation sequencing

Mixed phenotype acute leukemia (MPAL) is an uncommon manifestation of acute leukemia. The aim of this study is to further characterize the genetic landscape of de novo cases of MPAL that fulfill the 2016 World Health Organization (WHO) classification criteria for this entity. We identified 14 cases examined by next generation sequencing (NGS) using 28 (n = 10), 53 (n = 3) or 81 (n = 1) gene panels: 7 cases with a B-cell/myeloid (B/My) immunophenotype, 6 T-cell/myeloid (T/My) immunophenotype, and 1 B-cell/T-cell (B/T) immunophenotype. A total of 25 distinct mutations were identified in 15 different genes in 9/14 (64%) patients. FLT3-ITD was the only recurrent mutation in 2 patients. B/My MPAL cases less commonly harbored mutations compared with T/My MPAL cases (43% vs. 100%, p = 0.07). In contrast, B/My MPALs more commonly showed a complex karyotype compared to T/My MPALs (71% vs. 17%, p = 0.1). With NGS and karyotype combined, most (93%) MPAL cases had mutations or cytogenetic abnormalities. With a median follow-up of 12.5 months, there were no significant differences in median overall survival (OS) between patients with B/My or T/My MPAL (17.8 and 6.5 months, respectively, p = 0.81) or between patients with MPAL with versus without gene mutations (6.5 and 13.3 months, respectively, p = 0.86). Our data suggest that the distinguishing cases of MPAL according to immunophenotype has value because the underlying mechanisms of leukemogenesis might differ between B/My and T/My MPAL.

Mixed-Phenotype Acute Leukemia: Diagnostic Criteria and Pitfalls

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.

Mixed-phenotype acute leukemia: state-of-the-art of the diagnosis, classification and treatment

Mixed-phenotype acute leukemia (MPAL) is a heterogeneous group of hematopoietic malignancies in which blasts show markers of multiple developmental lineages and cannot be clearly classified as acute myeloid or lymphoblastic leukemias. Historically, various names and classifications were used for this rare entity accounting for 2-5% of all acute leukemias depending on the diagnostic criterias used. The currently valid classification of myeloid neoplasms and acute leukemia published by the World Health Organization (WHO) in 2016 refers to this group of diseases as MPAL. Because adverse cytogenetic abnormalities are frequently present, MPAL is generally considered a disease with a poor prognosis. Knowledge of its treatment is limited to retrospective analyses of small patient cohorts. So far, no treatment recommendations verified by prospective studies have been published. The reported data suggest that induction therapy for acute lymphoblastic leukemia followed by allogeneic hematopoietic cell transplantation is more effective than induction therapy for acute myeloid leukemia or consolidation chemotherapy. The establishment of cooperative groups and international registries based on the recent WHO criterias are required to ensure further progress in understanding and treatment of MPAL. This review summarizes current knowledge on the diagnosis, classification, prognosis and treatment of MPAL patients.

Bilineal Acute Leukemia Associated With Fanconi Syndrome: The First Case Report

Fanconi syndrome is a metabolic disorder involving dysfunction of the renal proximal tubules, resulting in excessive urinary excretion of several metabolites. Various factors may lead to Fanconi syndrome, as it may be a genetic disease with primary or secondary etiologies, or may be acquired. In this study, we report a unique case of Fanconi syndrome with development of a relatively rare acute leukemia, a condition that has not been reported before. The case was an 8-year-old boy with familial occurrence of Fanconi syndrome, presenting with pallor, asthenia, recurrent infections, growth failure, and a variety of biochemical and hematological abnormalities. After physical examination, radiographic studies, and comprehensive laboratory analyses, Fanconi syndrome associated with bilineal acute leukemia, of myeloid and T-lymphoid lineages, was diagnosed.

SERUM metabolomics of acute lymphoblastic leukaemia and acute myeloid leukaemia for probing biomarker molecules

Acute leukaemia (AL) is a critical neoplasm of white blood cells. Diagnosing AL requires bone marrow puncture procedure, which many patients do not consent to for it is invasive. Hence sensitive and specific early diagnostic biomarkers are essential for non-invasive diagnosis, new therapeutics and improving the disease prognosis. To differentiate the metabolic alterations associated with acute lymphoblastic leukaemia (ALL) and acute myeloid leukaemia (AML), we investigated serum of ALL and AML patients in comparison with two controls using gas chromatography coupled with triple quadrupole tandem mass spectrometry and multivariate statistical analysis. Twenty seven out of 1425 metabolites were found differentiative among ALL, AML, aplastic anaemia (APA) patients and healthy control using p-value ≤ 0.001. ALL is the most dissimilar group from other three groups as in hierarchical clustering showed 72.1% dissimilarity. Model generation using PLSDA gave an overall accuracy of 91.9%. This study helps in metabolic fingerprinting of control and disease serum at high significance levels and could be used for early diagnosing of AL. Based on pathways analysis, fatty acid metabolism is deregulated in patients with AL and may represent an underlying metabolic pathway associated with disease progression. Copyright © 2016 John Wiley & Sons, Ltd.

Two Elderly Patients with Philadelphia Chromosome Positive Mixed Phenotype Acute Leukemia Who Were Successfully Treated with Dasatinib and Prednisolone

Philadelphia chromosome positive (Ph+) mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia having both myeloid and lymphoid features for which no optimal treatment has yet been established. We herein describe two elderly Ph+MPAL patients who achieved molecular remission without any serious adverse events by treatment with dasatinib and prednisolone. Although dasatinib induction therapy combined with prednisolone is known to be a highly effective treatment for Ph+ acute lymphoblastic leukemia, its efficacy for Ph+MPAL has not been shown. The clinical courses of the present cases suggest that combination therapy with dasatinib and prednisolone is a safe and effective therapeutic modality in elderly Ph+MPAL patients.

Outcomes of allogeneic hematopoietic cell transplantation in patients with biphenotypic acute leukemia

The outcomes of allogeneic hematopoietic cell transplantation (HSCT) in patients with biphenotypic acute leukemia (BAL) remain unclear. We retrospectively analyzed the outcomes of HSCT in BAL patients in Japan in comparison to acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) using the registration data from a nationwide database. The data of 90, 5371, and 3301 patients with BAL, AML, and ALL, respectively, were included in the analysis. The median follow-up period was 1481.5 days (range: 0–5556). The 5-year overall survival (OS) of the BAL, AML, and ALL patients were 39.6, 41.8, and 42.0 %, respectively (BAL vs. AML, P = 0.98 BAL vs. ALL, P = 0.77). A multivariate analysis revealed that, in comparison to BAL, AML with a better-risk karyotype was associated with superior OS. An analysis of the prognostic factors of BAL patients showed that OS was significantly longer in patients who were in their first complete remission in comparison to patients who were not in remission. Our data suggest that HSCT is an effective treatment for BAL patients, regardless of the presence of any known poor prognostic factors other than a non-remission status.

Mixed Phenotype Acute Leukemia with Two Immunophenotypically Distinct B and T Blasts Populations, Double Ph (+) Chromosome and Complex Karyotype: Report of an Unusual Case

Mixed phenotype acute leukemia (MPAL) is considered as a rare type of leukemia with an incidence of less than 4% of all acute leukemia based on the most recent 2008 WHO classification. Common subtypes are the B/myeloid and T/myeloid; B/T and trilineage MPAL being extremely rare. We present a case of a male in his 20s, whose peripheral blood smears showed 34% blast cells and bone marrow with 70% blasts. Immunophenotyping by multiparametric flow cytometry showed two populations of blasts, the major one with B-lineage and the minor one with T-lineage. Conventional karyotyping revealed complex karyotype with the presence of double Philadelphia chromosome (Ph⁺). BCR/ABL1 rearrangement was confirmed by fluorescent in situ hybridization (FISH) analysis. The BCR/ABL1 ES probe on interphase cells indicated p190 minor m-BCR/ABL fusion in 46% and a second abnormal clone with double Ph⁺ in 16% of the cells analyzed confirmed by reverse transcription-PCR (RT-PCR). The case was diagnosed as MPAL with double Philadelphia chromosome Ph⁺. The patient was treated with dasatinib, four cycle hyper CVAD/methotrexate cytarabin protocol, and allogeneic transplant. He is still alive in complete hematological, cytogenetic, and molecular remission. Mixed phenotype B/T acute leukemia is an extremely rare disease, particularly those with double Philadelphia chromosomes and clinically presents challenges in diagnosis and treatment.

[The specific features of diagnosis of mixed-phenotype acute leukemia: A combination of B-cell antigen expressions according to the results of flow cytometry and morphological markers of myeloid differentiation in blast cells: A clinical case]

This rare type of acute leukemia, blast cells of which express myeloid and/or lymphoid markers, is mainly diagnosed using flow cytometric findings. The paper describes a clinical case of mixed-phenotype acute leukemia, in which B-cell lymphoid antigen expressions were revealed by a flow cytometric technique, while bone marrow morphological specimens showed the signs of myeloid differentiation specific to blast cells. It is concluded that there is a need for a comprehensive examination of patients with new-onset acute leukemia and for an aggregate analysis of flow cytometric results with morphological and cytochemical findings.

Establishment and genetic characterization of a novel mixed-phenotype acute leukemia cell line with EP300-ZNF384 fusion

Herein, we describe the establishment and characterization of the first mixed-phenotype acute leukemia cell line (JIH-5). The JIH-5 cell line was established from leukemia cells with B lymphoid/myeloid phenotype from a female mixed-phenotype acute leukemia patient. JIH-5 cells exhibit an immunophenotype comprised of myeloid and B lymphoid antigens. Whole-exome sequencing revealed somatic mutations in nine genes in JIH-5 cells. Transcriptional sequencing of JIH-5 cells identified EP300-ZNF384 fusion transcript, which is a recurrent alteration in B cell acute lymphoblastic leukemia. Our results suggest that the JIH-5 cell line may serve as a tool for the study of mixed-phenotype acute leukemia or EP300-ZNF384.

A Newborn with Congenital Mixed Phenotype Acute Leukemia After In Vitro Fertilization

Congenital leukemia is a rare disease. The majority of cases of this disease are acute myelogenous leukemia (AML). Congenital acute lymphoblastic leukemia (ALL) is rare and most often is of B cell lineage. Rarely, some cases have been designated biphenotypic or mixed phenotype acute leukemia (MPAL). Herein, we report a preterm newborn referred to us as a result of the appearance of blue-violaceous dermal nodules on her body at birth. She was a twin and the product of an in vitro fertilization (IVF) pregnancy. Physical examination showed jaundice, hepatosplenomegaly, and peripheral facial nerve palsy in addition to dermal nodules. Bone marrow aspiration showed 40% blasts of lymphoid lineage; skin biopsy and its immunohistochemistry revealed myeloblastic infiltration of the dermis. Cytogenetic analysis (46,XX), fluorescence in situ hybridization (FISH) analysis, and cranial magnetic resonance were normal. The patient was diagnosed with congenital MPAL, and an association between IVF and congenital leukemia was suggested.

The relationship between clinical feature, complex immunophenotype, chromosome karyotype, and outcome of patients with acute myeloid leukemia in China

Mixed phenotype acute leukemia (MPAL) is a complex entity expressing both lymphoid and myeloid immunophenotyping. In the present study, 47 MPAL, 60 lymphoid antigen-positive acute myeloid leukemia (Ly⁺AML), and 90 acute myeloid leukemia with common myeloid immunophenotype (Ly⁻AML) patients were investigated. We found that, in MPAL patients, there were high proportions of blast cells in bone marrow and incidence of hepatosplenomegaly, lymphadenopathy, and Philadelphia chromosome. The overall survival (OS) and relapse-free survival (RFS) in MPAL patients were significantly shorter than those in Ly⁺AML and Ly⁻AML. With regard to the patients with normal karyotype only, the OS and RFS of MPAL were significantly lower than those of the Ly⁺AML and Ly⁻AML; but there were no significant differences in OS and RFS among the patients with complex karyotype. The OS rates of 3 groups with complex karyotype were lower than those of patients with normal karyotype. In Cox multivariate analysis, complex karyotype was an independent pejorative factor for both OS and RFS. Therefore, MPAL is confirmed to be a poor-risk disease while Ly⁺AML does not impact prognosis. Complex karyotype is an unfavorable prognosis factor in AML patients with different immunophenotype. Mixed immunophenotype and complex karyotype increase the adverse risk when they coexist.

How I treat mixed-phenotype acute leukemia

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.

T-cell acute lymphoid leukemia resembling Burkitt leukemia cell morphology: A case report

Biphenotypic acute leukemia (BAL) is an uncommon type of cancer, which accounts for <5% of all adult ALs. Based upon a previously described scoring system, the European Group for the Immunological Classification of Leukemias (EGIL) proposed a set of diagnostic criteria for BAL. This scoring system is based upon the number and degree of specificity of several markers for myeloid or T/B-lymphoid blasts. The present study describes a case of T-cell acute lymphoblastic leukemia (T-ALL) with Burkitt-like cytology, which according to the French-American-British classification, corresponded to a diagnosis of Burkitt type L3 ALL. Flow cytometry analysis demonstrated that the blasts were positive for T-lymphoid markers, cytoplasmic cluster of differentiation (CD)3, CD7 and CD56, and myeloid markers, CD13, CD33 and CD15. At first, a diagnosis of BAL was suggested by the EGIL score, however, according to the 2008 World Health Organization criteria, a case of T-ALL with aberrant myeloid markers was established. The study also reviewed the literature and discussed the limitations of the EGIL scoring system in clinical decision making, to aid in the selection of an appropriate therapeutic regimen.

Children Diagnosed as Mixed-Phenotype Acute Leukemia Didn't Benefit from the CCLG-2008 Protocol, Retrospective Analysis from Single Center

Mixed phenotype acute leukemia (MPAL) is a rare type of acute leukemia with a poor clinical outcome which lacks specific therapy. To evaluate the therapeutic efficiency of CCLG-2008 protocol used for acute lymphoblastic leukemia (ALL) in China on MPAL children who were initially diagnosed as ALL by morphology, we reviewed patients' database diagnosed as ALL and MPAL according to WHO classification and compared their outcomes from July 2008 to June 2012. Total newly enrolled ALL in this study were 309 cases by morphology, in which ten cases were identified as MPAL mainly by immunophenotyping: B+ myeloid (3/10), T+ myeloid (2/10), B + T (4/10), trilineage (1/10). Two cases were classified as intermediate risk (IR) and 8 cases were high risk (HR) according to the CCLG-2008 criteria. Only one case of IR survived and others died due to primary resistance of chemotherapy and relapse. Compared with MPAL, ALL children in IR and HR had a longer survival (28.1 vs 9.5 months, p < 0.0001) and lower relapse (16.3 vs 85.7 %, p = 0.0002). In a summary, our result indicated that MPAL in children is a poor-risk disease which needs personalized therapy to improve outcome.

A Bi-Lineal Acute Leukemia (T/Myeloid, NOS) with Complex Cytogenetic Abnormalities

We report an unusual case of bi-lineal mixed-phenotype acute leukemia (T/Myeloid, NOS) with complex cytogenetic abnormalities in a 2-year-old boy. Despite attaining complete remission with therapy, he succumbed to status epilepticus following febrile illness. Flow cytometry represents the current standard of care for the diagnosis of this malignancy and the approach adopted in our case is discussed.