BTK, NuTM2A, and PRPF19 are Novel KMT2A Partner Genes in Childhood Acute Leukemia

Chromosomal rearrangements of the human KMT2A/MLL gene are associated with acute leukemias, especially in infants. KMT2A is rearranged with a big variety of partner genes and in multiple breakpoint locations. Detection of all types of KMT2A rearrangements is an essential part of acute leukemia initial diagnostics and follow-up, as it has a strong impact on the patients’ outcome. Due to their high heterogeneity, KMT2A rearrangements are most effectively uncovered by next-generation sequencing (NGS), which, however, requires a thorough prescreening by cytogenetics. Here, we aimed to characterize uncommon KMT2A rearrangements in childhood acute leukemia by conventional karyotyping, FISH, and targeted NGS on both DNA and RNA level with subse-quent validation. As a result of this comprehensive approach, three novel KMT2A rearrangements were discovered: ins(X;11)(q26;q13q25)/KMT2A-BTK, t(10;11)(q22;q23.3)/KMT2A-NUTM2A, and inv(11)(q12.2q23.3)/KMT2A-PRPF19. These novel KMT2A-chimeric genes expand our knowledge of the mechanisms of KMT2A-associated leukemogenesis and allow tracing the dynamics of minimal residual disease in the given patients. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: KMT2A rearrangement assessment was supported by the Russian Science Foundation (grant no. 19-75-10056). Quantitative RT-PCR for MRD monitoring was supported by Russian Presidential (grant no. MK-1645.2020.7)

Дебют воспалительной скелетно-мышечной патологии у пациентов, получающих противоопухолевое лечение ингибиторами PD-1/PD-L1-пути

Objective: to describe musculoskeletal immune-mediated adverse events (iAEs) associated with the therapy of solid tumors with immune checkpoint inhibitors (ICIs, inhibitors of the PD-1/PD-L1 pathway).Patients and methods. 13 patients receiving ICIs therapy with musculoskeletal iAEs were examined. The average age of patients was 59±10 years. All cases had a histologically verified diagnosis of a malignant solid neoplasm: melanoma (n=5), kidney cancer (n=3), bladder cancer (n=2), non-small cell lung cancer (n=1), breast cancer (n=1), cervical cancer (n=1). All patients were prescribed inhibitors of the PD-1/PD-L1 signaling pathway: nivolumab (n=6), pembrolizumab (n=3), atezolizumab (n=3), prolgolimab (n=1). In 7 (54%) patients, in addition to musculoskeletal disorders, other AEs were also detected: thyroiditis (n=3), neuropathy (n=2), rash (n=1), dry syndrome (n=1), hepatitis (n=1). The median time from the start of antitumor immunotherapy (IT) to the onset of musculoskeletal pathology was 20 [9; 48] weeks.Results and discussion. Clinical manifestations of musculoskeletal pathology included: synovitis in 9 (69%) patients, tenosynovitis in 11 (85%), enthesitis in 4 (31%), morning stiffness in the joints for more than 30 minutes in 4 (31%). In 11 cases, musculoskeletal pathology was persistent (in 9 patients with arthritis and 2 with periarthritis) and in 2 – transient. The knee (77%), shoulder (69%) and hand (54%) joints were most frequently affected, with bilateral involvement in 9 (69%) patients. Inflammatory changes in the joints were represented by mono- (n=1), oligo- (n=3) and polyarthritis (n=5), including those involving the small joints of the hands and/or feet (n=5) and predominantly affecting the joints of the lower limbs (n=3). In 3 patients with arthritis, periarticular changes dominated in clinical picture (in 2 patients with symmetrical polyarthritis and severe tenosynovitis, in another 1 patient – with RS3PE syndrome). The severity of musculoskeletal pathology was assessed using the CTCAE v5.0 toxicity criteria: grade 1 was documented in 2 (15.5%), grade 2 in 9 (69%), and grade 3 in 2 (15, 5%) patients. Laboratory workup revealed elevation of ESR ≥30 mm/h (median – 34 [14; 42] mm/h) in 7 out of 12 (58%) patients, elevation of CRP level >5 mg/l (median – 7.2 [4.6; 12.9] mg/l) – in 7 out of 10 (70%). In 7 out of 10 patients, antinuclear antibodies (Hep2) were detected in titers: 1:160 (n=2), 1:320 (n=3), 1:640 (n=2). Rheumatoid factor and antibodies to cyclic citrullinated peptide were not detected in any case. Therapy for musculoskeletal AEs included non-steroidal anti-inflammatory drugs (n=10), oral systemic glucocorticoids – GC (n=5), methotrexate – MT (n=1) and hydroxychloroquine (n=5), intra-articular administration of GC (n=1). Five patients with arthritis required long-term therapy (median duration – 12 [3; 12] months), in 1 patient with polyarthritis and severe tenosynovitis, antitumor IT was interrupted for the duration of the course of MTX treatment.Conclusion. It has been shown that musculoskeletal iAEs have heterogeneous manifestations and may require long-term treatment and in rare cases, anticancer therapy interruption. Additional studies and close cooperation between rheumatologists and oncologists are needed to obtain a more complete understanding of the nature and spectrum of musculoskeletal AEs, to identify their clinical, laboratory and instrumental features, and to develop an management of patients algorithm.Цель исследования – описать скелетно-мышечные иммуноопосредованные нежелательные явления (иНЯ), ассоциированные с терапией солидных опухолей ингибиторами контрольных точек (ИКТ, ингибиторы PD-1/PD-L1-пути).Пациенты и методы. Обследовано 13 пациентов со скелетно-мышечными иНЯ, получающих терапию ИКТ. Средний возраст больных – 59±10 лет. Всех случаях имелся гистологически верифицированный диагноз злокачественного солидного новообразования: меланома (n=5), рак почки (n=3), рак мочевого пузыря (n=2), немелкоклеточный рак легкого (n=1), рак молочной железы (n=1), рак шейки матки (n=1). Всем пациентам были назначены ингибиторы сигнального пути PD-1/PD-L1: ниволумаб (n=6), пембролизумаб (n=3), атезолизумаб (n=3), пролголимаб (n=1). У 7 (54%) пациентов, кроме скелетно-мышечных нарушений, также выявлялись другие иНЯ: тиреоидит (n=3), невропатия (n=2), сыпь (n=1), сухой синдром (n=1), гепатит (n=1). Медиана времени от начала противоопухолевой иммунотерапии (ИТ) до дебюта скелетно-мышечной патологии составила 20 [9; 48] нед.Результаты и обсуждение. Клинические проявления скелетно-мышечной патологии включали: синовит у 9 (69%) больных, теносиновит у 11 (85%), энтезит у 4 (31%), утреннюю скованность в суставах более 30 мин у 4 (31%). В 11 случаях скелетномышечная патология носила персистирующий характер (у 9 пациентов с артритом и 2 с периартритом) и в 2 – транзиторный. Наиболее часто поражались коленные (77%), плечевые (69%) суставы и суставы кистей (54%) с двусторонним вовлечением у 9 (69%) пациентов. Воспалительные изменения суставов были представлены моно- (n=1), олиго- (n=3) и полиартритом (n=5), в том числе с вовлечением мелких суставов кистей и/или стоп (n=5) и преимущественным поражением суставов нижних конечностей (n=3). У 3 больных с артритом в клинической картине преобладали периартикулярные изменения (у 2 пациентов с симметричным полиартритом и тяжелым теносиновитом, еще у 1 – с RS3PE-синдромом). Тяжесть скелетно-мышечной патологии была оценена с помощью критериев токсичности CTCAE v5.0: 1-я степень установлена у 2 (15,5%), 2-я – у 9 (69%) и 3-я – у 2 (15,5%) пациентов. При лабораторном обследовании увеличение СОЭ ≥30 мм/ч (медиана – 34 [14; 42] мм/ч) выявлено у 7 из 12 (58%) больных, повышение уровня СРБ >5 мг/л (медиана – 7,2 [4,6; 12,9] мг/л) – у 7 из 10 (70%). У 7 из 10 больных обнаружен антинуклеарный фактор (Hep2) в титрах: 1:160 (n=2), 1:320 (n=3), 1:640 (n=2). Ревматоидный фактор и антитела к циклическому цитруллинированному пептиду не выявлены ни в одном случае. Терапия скелетно-мышечных иНЯ включала применение нестероидных противовоспалительных препаратов (n=10), оральных системных глюкокортикоидов – ГК (n=5), метотрексата – МТ (n=1) и гидроксихлорохина (n=5), внутрисуставное введение ГК (n=1). Пять пациентов с артритом нуждались в продолжительной терапии (медиана длительности – 12 [3; 12] мес), у 1 пациента с полиартритом и тяжелым теносиновитом противоопухолевая ИТ была прервана на время проведения курса лечения МТ.Заключение. Показано, что скелетно-мышечные иНЯ имеют гетерогенные проявления и могут потребовать длительного лечения, а в редких случаях – и приостановки противоопухолевой терапии. Для получения более полного представления о природе и спектре скелетно-мышечных иНЯ, выделения их клинико-лабораторных и инструментальных особенностей, разработки алгоритма курации необходимы дополнительные исследования и тесное сотрудничество ревматологов и онкологов

The role of nelarabine in the treatment of T-cell acute lymphoblastic leukemia: literature review and own experience

Aim. The analysis of experience of nelarabine use in refractory/relapsed T-cell acute lymphoblastic leukemia (T-ALL) depending on the immunophenotype and the line of therapy. Materials and methods. All the patients with relapsed or refractory T-ALL aged from 0 to 18 years who received treatment with nelarabine as a part of the therapeutic element R6 were included in the study. For all patients a detailed immunological analysis of leukemia cells with discrimination of immunological variants TI, TII, TIII or TIV was performed. Patients administered with nelarabine as a first therapeutic element were referred to the first-line therapy group, other patients were referred to the second-line therapy group. Nelarabine was administered as intravenous infusion at a dose of 650 mg/m2, on days 1-5. Allogeneic hematopoietic stem cells transplantation (allo-HSCT) was considered for all patients. Results. From 2009 to 2017, 54 patients with refractory/relapsed T-ALL were treated with nelarabine. Five-year event-free survival (EFS) and overall survival (OS) was 28% for all patients, cumulative risk of relapse (CIR) was 27%. EFS was significantly higher in nelarabine first-line therapy group in comparison with second-line therapy group (34±8% vs 8±8%, p=0,05). In patients after allo-HSCT EFS, OS and CIR were 51±10%, 50±10% and 39,1±9,5% accordingly. The best results were achieved in patients with TI immunophenotype. No toxicity-related mortality as well as severe neurologic complications or discontinuation of therapy associated with use of nelarabine were reported. Conclusion. The use of nelarabine is an effective strategy for the treatment of relapsed and refractory T-ALL. The best treatment outcomes were obtained in patients with TI immunophenotype and in the first-line therapy group. Optimal dosage regimens can be established during controlled clinical trials

The MLL recombinome of acute leukemias in 2017

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients

Epigenetic regulator genes direct lineage switching in MLL/AF4 leukaemia

The fusion gene MLL/AF4 defines a high-risk subtype of pro-B acute lymphoblastic leukaemia. Relapse can be associated with a lineage switch from acute lymphoblastic to acute myeloid leukaemia resulting in poor clinical outcomes due to resistance towards chemo- and immuno-therapies. Here we show that the myeloid relapses share oncogene fusion breakpoints with their matched lymphoid presentations and can originate from varying differentiation stages from immature progenitors through to committed B-cell precursors. Lineage switching is linked to substantial changes in chromatin accessibility and rewiring of transcriptional programmes, including alternative splicing. These findings indicate that the execution and maintenance of lymphoid lineage differentiation is impaired. The relapsed myeloid phenotype is recurrently associated with the altered expression, splicing or mutation of chromatin modifiers, including CHD4 coding for the ATPase/helicase of the nucleosome remodelling and deacetylation complex, NuRD. Perturbation of CHD4 alone or in combination with other mutated epigenetic modifiers induces myeloid gene expression in MLL/AF4-positive cell models indicating that lineage switching in MLL/AF4 leukaemia is driven and maintained by disrupted epigenetic regulation

The MLL recombinome of acute leukemias in 2017

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients.</p

The MLL recombinome of acute leukemias in 2017

Chromosomal rearrangements of the human MLL/KMT2A gene are associated with infant, pediatric, adult and therapy-induced acute leukemias. Here we present the data obtained from 2345 acute leukemia patients. Genomic breakpoints within the MLL gene and the involved translocation partner genes (TPGs) were determined and 11 novel TPGs were identified. Thus, a total of 135 different MLL rearrangements have been identified so far, of which 94 TPGs are now characterized at the molecular level. In all, 35 out of these 94 TPGs occur recurrently, but only 9 specific gene fusions account for more than 90% of all illegitimate recombinations of the MLL gene. We observed an age-dependent breakpoint shift with breakpoints localizing within MLL intron 11 associated with acute lymphoblastic leukemia and younger patients, while breakpoints in MLL intron 9 predominate in AML or older patients. The molecular characterization of MLL breakpoints suggests different etiologies in the different age groups and allows the correlation of functional domains of the MLL gene with clinical outcome. This study provides a comprehensive analysis of the MLL recombinome in acute leukemia and demonstrates that the establishment of patient-specific chromosomal fusion sites allows the design of specific PCR primers for minimal residual disease analyses for all patients