First report of familial mixed phenotype acute leukemia: shared clinical characteristics, Philadelphia translocation, and germline variants.

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.

Clinico-hematological and immunophenotypic profile of acute leukemia of ambiguous lineage: A four year experience from a single tertiary care centre of West India.

Background: : Acute leukemia of ambiguous lineage (ALAL) is a heterogeneous group of rare leukemias that lacks definite evidence of differentiation along one lineage. It includes acute undifferentiated leukemia and mixed-phenotype acute Leukaemia (MPAL). Aims: The present study highlighted the clinicohematological and immunophenotypic profile of ALAL cases diagnosed in the tertiary care centre of western India. Study Design: Retrospective observational study. Methods and Materials: Patients diagnosed with acute leukemia, preferably their bone marrow aspirate samples, were collected in ethylene diamine tetra-acetic acid-vial. The immunophenotypic study was done using the Fluorescence Activated Cell Sorting (FACS) Canto Eight color flow cytometer and a broad panel of monoclonal antibodies. The patients were diagnosed for ALAL, based on the World Health Organization (WHO) 2017 classification. Statistical Analysis Used: Descriptive statistics with categorical and continuous variables. Results: Overall incidence of ALAL was about 2.1%, and singly MPAL and AUL were 1.8%, and 0.3%, in frequency, respectively. The age range was 4 to 57 (median age 21 years), of which 11 (57.9%) were adults and eight were children (42.1%). There was male predominance with Male: Female ratio of 5.3:1. On immunophenotyping, B/myeloid MPAL (42.1%) was the commonest among the ALAL. Translocation t(9;22) was the most common cytogenetic abnormality found mainly in B/myeloid MPAL. Two cases were of chronic myeloid leukemia in a mixed phenotypic blast crisis. Over all prognosis of ALAL was poor. Conclusion: ALAL is overall associated with poor prognosis as both their diagnosis and treatment decisions are difficult owing to the lack of optimum treatment data and the rarity of the disease. Hence, A careful diagnosis with the help of immunophenotyping is crucial.

Resultados preliminares tras la instauración del programa con medicamentos CAR-T en leucemia aguda linfoblástica en un centro pediátrico / Building a CAR-T cell therapy program in a pediatric hemato-oncology department. Preliminary data

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Influence of minimal residual disease by multiparametric flow cytometry at day 15 of induction in risk stratification of children with B-cell acute lymphoblastic leukemia treated at a referral hospital in southern Brazil

ABSTRACT Background: The minimal residual disease (MRD) is the most important prognostic factor for acute lymphoblastic leukemia (ALL) in children. This study aimed to investigate the influence of detecting the MRD by the multiparametric flow cytometry (MFC) at day 15 (D15) of the induction on the analysis of the risk group classifications of the different childhood ALL treatment protocols used in a referral hospital in southern Brazil. Method: We retrospectively reviewed the medical records of patients with B-cell ALL, aged 1 to 18 years, treated at a hospital from January 2013 to April 2017. Main results: Seventy-five patients were analyzed. Regarding the MRD by the MFC at D15, the analyses showed statistical significance when the MRD was grouped into three categories, < 0.1%, 0.1-10%, and > 10%, with the following distribution: 30.7%, 52.0%, and 17.3%, respectively. There was a significant association between D15 MRD-MFC < 0.1% and the likelihood of dying or relapsing and between D15 MRD-MFC > 10% and the likelihood of dying or relapsing. The cumulative hazard ratio for the relapse of patients with D15 MRD-MFC < 0.1%, 0.1-10%, and > 10% was 19.2%, 59.8%, and 80.1%, respectively. Conclusion: Our analysis suggests D15 MRD-MFC < 0.1% as a cut-off point for patients with more favorable outcomes and that the MRD at D15 in risk classifications is particularly useful for the stratification of patients with a more favorable prognosis.

Neoplasia de células dendríticas blásticas plasmacitoides. Estudio de tres casos / Blastic plasmacytoid dendritic cell neoplasm. A study of three cases

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Mixed phenotype acute leukemia: Biological profile, clinical characteristic and treatment outcomes: Report of the population-based study.

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.

Mixed-phenotype acute leukemia: A cohort and consensus research strategy from the Children's Oncology Group Acute Leukemia of Ambiguous Lineage Task Force.

BACKGROUND: Optimal chemotherapy for treating mixed-phenotype acute leukemia (MPAL) and the role of hematopoietic stem cell transplantation (HSCT) remain uncertain. Major limitations in interpreting available data are MPAL's rarity and the use of definitions other than the currently widely accepted criteria: the World Health Organization 2016 (WHO2016) classification. METHODS: To assess the relative efficacy of chemotherapy types for treating pediatric MPAL, the Children's Oncology Group (COG) Acute Leukemia of Ambiguous Lineage Task Force assembled a retrospective cohort of centrally reviewed WHO2016 MPAL cases selected from banking studies for acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML). Patients were not treated in COG trials; treatment and outcome data were captured separately. The findings were then integrated with the available, mixed literature to develop a prospective trial in pediatric MPAL. RESULTS: The central review confirmed that 54 of 70 cases fulfilled WHO2016 criteria for MPAL. ALL induction regimens achieved remission in 72% of the cases (28 of 39), whereas AML regimens achieved remission in 69% (9 of 13). The 5-year event-free survival (EFS) and overall survival (OS) rates for the entire cohort were 72% ± 8% and 77% ± 7%, respectively. EFS and OS were 75% ± 13% and 84% ± 11%, respectively, for those receiving ALL chemotherapy alone without HSCT (n = 21). CONCLUSIONS: The results of the COG MPAL cohort and a literature review suggest that ALL chemotherapy without HSCT may be the preferred initial therapy. A prospective trial within the COG is proposed to investigate this approach; AML chemotherapy and/or HSCT will be reserved for those with treatment failure as assessed by minimal residual disease. Embedded biology studies will provide further insight into MPAL genomics.

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.

Improving Clinical Manufacturing of IL-15 Activated Cytokine-Induced Killer (CIK) Cells.

Cytokine-induced killer (CIK) cells are an immunotherapeutic approach to combat relapse following allogeneic hematopoietic stem cell transplantation (HSCT) in acute leukemia or myelodysplastic syndrome (MDS) patients. Prompt and sequential administration of escalating cell doses improves the efficacy of CIK cell therapy without exacerbating graft vs. host disease (GVHD). This study addresses manufacturing-related issues and aimed to develop a time-, personal- and cost-saving good manufacturing process (GMP)-compliant protocol for the generation of ready-for-use therapeutic CIK cell doses starting from one unstimulated donor-derived peripheral blood (PB) or leukocytapheresis (LP) products. Culture medium with or without the addition of either AB serum, fresh frozen plasma (FFP) or platelet lysate (PL) was used for culture. Fresh and cryopreserved CIK cells were compared regarding expansion rate, viability, phenotype, and ability to inhibit leukemia growth. Cell numbers increased by a median factor of 10-fold in the presence of FFP, PL, or AB serum, whereas cultivation in FFP/PL-free or AB serum-free medium failed to promote adequate CIK cell proliferation (p < 0.01) needed to provide clinical doses of 1 × 106 T cells/kG, 5 × 106 T cells/kG, 1 × 107 T cells/kG, and 1 × 108 T cells/kG recipient body weight. CIK cells consisting of T cells, T- natural killer (T-NK) cells and a minor fraction of NK cells were not significantly modified by different medium supplements. Moreover, neither cytotoxic potential against leukemic THP-1 cells nor cell activation shown by CD25 expression were significantly influenced. Moreover, overnight and long-term cryopreservation had no significant effect on the composition of CIK cells, their phenotype or cytotoxic potential. A viability of almost 93% (range: 89-96) and 89.3% (range: 84-94) was obtained after freeze-thawing procedure and long-term storage, respectively, whereas viability was 96% (range: 90-97) in fresh CIK cells. Altogether, GMP-complaint CIK cell generation from an unstimulated donor-derived PB or LP products was feasible. Introducing FFP, which is easily accessible, into CIK cell cultures was time- and cost-saving without loss of viability and potency in a 10-12 day batch culture. The feasibility of cryopreservation enabled storage and delivery of sequential highly effective ready-for-use CIK cell doses and therefore reduced the number of manufacturing cycles.

Multiparameter flow cytometry applications in the diagnosis of mixed phenotype acute leukemia.

Mixed phenotype acute leukemias (MPALs) represent a rare subgroup of acute leukemias with a poor prognosis. Proper diagnosis and classification of MPAL is extremely important for patients' outcome. Morphology and flow cytometry recognize two types of MPAL: the "bilineal" MPAL with the coexistence of two blast populations of different lineage and truly "biphenotypic" MPAL coexpressing markers of more than one lineage in a homogenous blast population, respectively. The WHO 2008 classification further delineated three categories: associated with t(9;22)/BCR-ABL1 fusion gene, associated with KMT2A (mixed lineage leukemia) rearrangements, and nonotherwise specified. These categories remained unchanged in the WHO2016 update. Molecular studies have further underlined the heterogeneity of MPAL. In this review, rules for the correct assignment of acute leukemia to the MPAL category are discussed, including both flow cytometry and immunohistochemistry on bone marrow or other tissues biopsies. Comparison of the immunophenotypic classification proposals is provided outlining the explorations mandatory for definitive diagnosis. An extensive review of published data summarizes the reported cytogenetic and molecular anomalies. New developments in the understanding of the early stages of hematopoiesis provide clues to the possible etiopathology of these diseases. Finally, current treatment recommendations are summarized and referenced for clinical use, pointing out that allogeneic hematopoietic stem cell transplantation at an early stage should be considered (at least in adult patients). © 2019 International Clinical Cytometry Society.

Genomic and clinical characterization of B/T mixed phenotype acute leukemia reveals recurrent features and T-ALL like mutations.

The B/T subtype of mixed phenotype acute leukemia (B/T MPAL) is defined by co-expression of antigens of both B- and T-cell lineages on leukemic blasts. Although it has been suggested that multilineage antigen expression portends poor response to chemotherapy, the clinical characteristics and driver mutations that underlie the pathogenesis of this rare subtype of acute leukemia are scarcely known. We identified nine cases of B/T MPAL from multiple institutions and correlated clinical and immunophenotypic findings with next-generation sequencing data. We report that B/T MPAL commonly presents with lymphadenopathy in adolescence and young adulthood. While the tumors have diverse cytogenetic and genomic perturbations, recurrent acquired aberrations include mutations in the putative transcriptional regulator PHF6 and the JAK-STAT and Ras signaling pathways. Alterations were also identified in genes encoding hematopoietic transcription factors, cell cycle regulators/tumor suppressors, and chromatin modifying enzymes. The genomic landscape of B/T MPAL strongly resembles that of T-ALL subgroups associated with early developmental arrest, while genetic alterations that are common in B-ALL were rarely seen. Two-thirds of the patients responded to ALL-based chemotherapy with or without stem cell transplantation. Our observations lay the groundwork for further study of the unique biology and clinical trajectory of B/T MPAL.

Integrative genomic analysis of adult mixed phenotype acute leukemia delineates lineage associated molecular subtypes.

Mixed phenotype acute leukemia (MPAL) is a rare subtype of acute leukemia characterized by leukemic blasts presenting myeloid and lymphoid markers. Here we report data from integrated genomic analysis on 31 MPAL samples and compare molecular profiling with that from acute myeloid leukemia (AML), B cell acute lymphoblastic leukemia (B-ALL), and T cell acute lymphoblastic leukemia (T-ALL). Consistent with the mixed immunophenotype, both AML-type and ALL-type mutations are detected in MPAL. Myeloid-B and myeloid-T MPAL show distinct mutation and methylation signatures that are associated with differences in lineage-commitment gene expressions. Genome-wide methylation comparison among MPAL, AML, B-ALL, and T-ALL sub-classifies MPAL into AML-type and ALL-type MPAL, which is associated with better clinical response when lineage-matched therapy is given. These results elucidate the genetic and epigenetic heterogeneity of MPAL and its genetic distinction from AML, B-ALL, and T-ALL and further provide proof of concept for a molecularly guided precision therapy approach in MPAL.

International cooperative study identifies treatment strategy in childhood ambiguous lineage leukemia.

Despite attempts to improve the definitions of ambiguous lineage leukemia (ALAL) during the last 2 decades, general therapy recommendations are missing. Herein, we report a large cohort of children with ALAL and propose a treatment strategy. A retrospective multinational study (International Berlin-Frankfurt-Münster Study of Leukemias of Ambiguous Lineage [iBFM-AMBI2012]) of 233 cases of pediatric ALAL patients is presented. Survival statistics were used to compare the prognosis of subsets and types of treatment. Five-year event-free survival (EFS) of patients with acute lymphoblastic leukemia (ALL)-type primary therapy (80% ± 4%) was superior to that of children who received acute myeloid leukemia (AML)-type or combined-type treatment (36% ± 7.2% and 50% ± 12%, respectively). When ALL- or AML-specific gene fusions were excluded, 5-year EFS of CD19+ leukemia was 83% ± 5.3% on ALL-type primary treatment compared with 0% ± 0% and 28% ± 14% on AML-type and combined-type primary treatment, respectively. Superiority of ALL-type treatment was documented in single-population mixed phenotype ALAL (using World Health Organization and/or European Group for Immunophenotyping of Leukemia definitions) and bilineal ALAL. Treatment with ALL-type protocols is recommended for the majority of pediatric patients with ALAL, including cases with CD19+ ALAL. AML-type treatment is preferred in a minority of ALAL cases with CD19- and no other lymphoid features. No overall benefit of transplantation was documented, and it could be introduced in some patients with a poor response to treatment. As no clear indicator was found for a change in treatment type, this is to be considered only in cases with ≥5% blasts after remission induction. The results provide a basis for a prospective trial.

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.