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A letter to the editor is presented which discusses the success of the xenografts of acute myeloid leukemia 3 (AML3) samples in immunodeficient mice.

The article discusses the rare occurrence of disseminated skin involvement in patients with HIV-associated Burkitt lymphoma (BL). Topics discussed include the histopathological, clinical and cytogenetic features of skin involvement in BL associated with HIV, the histopathological differential diagnosis of BL, and the poor short-term prognosis in the patients.

Inflammation in Waldenström Macroglobulinemia (iWM) predicts outcomes after immuno-chemotherapy and BTK inhibitors, but its origin is unknown. Here, we unravel increased clonal hematopoiesis in iWM patients (61% versus 23% in non-inflammatory WM), suggesting a contribution of environmental cells to iWM., (Copyright © 2024 American Society of Hematology.)

Genetic alterations are the cornerstone of risk stratification in B-cell precursor acute lymphoblastic leukemia (BCP-ALL), and their accurate identification is critical for optimal treatment. Most cases with ABL-class fusion are classified as high-risk yet display good responses to tyrosine kinase inhibitors (TKIs). Current clinical protocols recommend adding a TKI to chemotherapy as soon as possible, making it mandatory to rapidly identify these alterations. We investigated here whether the identification of immunophenotypic features associated with these molecular alterations could be a valuable screening tool. CD36 expression was shown to be a characteristic feature of ABL- or JAK-class kinase fusions. The main genetic subgroups clustering in the subset with Philadelphia (Ph)-like features were also found to display specific immunophenotypic characteristics. A predictive multiparameter scoring system was generated, segregating genetic subtypes with aberrant kinase activation (PAX5/CRLF2alt, BCR::ABL1, ABL/JAK-class). The most robust markers identified were the TSLPR with CD19/22/9/38/81/304 and CD49f. As TKI adjunction is currently limited to the ABL-class kinase fusions, immunophenotypes distinguishing ABL from JAK-class were also investigated. The flow cytometry method reported here, accessible to most hematology departments, is thus a new useful tool to quickly screen for Ph-like kinase fusion with a good sensitivity (95%) and specificity (96%)., (© 2024. The Author(s), under exclusive licence to Springer Nature Limited.)

Low hypodiploidy defines a rare subtype of B-cell acute lymphoblastic leukemia (B-ALL) with a dismal outcome. To investigate the genomic basis of low-hypodiploid ALL (LH-ALL) in adults, we analyzed copy-number aberrations, loss of heterozygosity, mutations, and cytogenetics data in a prospective cohort of Philadelphia (Ph)-negative B-ALL patients (n = 591, ages 18-84 years), allowing us to identify 80 LH-ALL cases (14%). Genomic analysis was critical for evidencing low hypodiploidy in many cases missed by cytogenetics. The proportion of LH-ALL within Ph-negative B-ALL dramatically increased with age, from 3% in the youngest patients (under 40 years old) to 32% in the oldest (over 55 years old). Somatic TP53 biallelic inactivation was the hallmark of adult LH-ALL, present in virtually all cases (98%). Strikingly, we detected TP53 mutations in posttreatment remission samples in 34% of patients. Single-cell proteogenomics of diagnosis and remission bone marrow samples evidenced a preleukemic, multilineage, TP53-mutant clone, reminiscent of age-related clonal hematopoiesis., Significance: We show that low-hypodiploid ALL is a frequent entity within B-ALL in older adults, relying on somatic TP53 biallelic alteration. Our study unveils a link between aging and low-hypodiploid ALL, with TP53-mutant clonal hematopoiesis representing a preleukemic reservoir that can give rise to aneuploidy and B-ALL. See related commentary by Saiki and Ogawa, p. 102. This article is highlighted in the In This Issue feature, p. 101., (©2023 The Authors; Published by the American Association for Cancer Research.)

Fanconi anemia (FA) patients experience chromosome instability, yielding hematopoietic stem/progenitor cell (HSPC) exhaustion and predisposition to poor-prognosis myeloid leukemia. Based on a longitudinal cohort of 335 patients, we performed clinical, genomic, and functional studies in 62 patients with clonal evolution. We found a unique pattern of somatic structural variants and mutations that shares features of BRCA-related cancers, the FA-hallmark being unbalanced, microhomology-mediated translocations driving copy-number alterations. Half the patients developed chromosome 1q gain, driving clonal hematopoiesis through MDM4 trisomy downmodulating p53 signaling later followed by secondary acute myeloid lukemia genomic alterations. Functionally, MDM4 triplication conferred greater fitness to murine and human primary FA HSPCs, rescued inflammation-mediated bone marrow failure, and drove clonal dominance in FA mouse models, while targeting MDM4 impaired leukemia cells in vitro and in vivo. Our results identify a linear route toward secondary leukemogenesis whereby early MDM4-driven downregulation of basal p53 activation plays a pivotal role, opening monitoring and therapeutic prospects., Competing Interests: Declaration of interests J.S. is scientific advisor for STRM.BIO, Inc (Boston, USA)., (Copyright © 2023. Published by Elsevier Inc.)

Hyperviscosity syndrome (HVS) is a rare complication of newly diagnosed multiple myeloma (NDMM) related to high tumour burden. Studies about the prognosis of HVS in modern-era therapy for NDMM are missing. We investigated a retrospective cohort study of NDMM with HVS between 2011-2021. Thirty-nine NDMM patients with HVS were included. HVS presentation was heterogeneous, with asymptomatic, mild, and neurological forms in 23%, 59%, and 18% of cases, respectively. No thrombosis or major bleeding was observed. Therapeutic plasma exchanges were used in 92% of patients, which were effective and well tolerated. No rebound effect was observed. All patients except one had at least one CRAB criterion. Most of the patients received bortezomib and high-dose steroids (95%) associated with an immunomodulatory drug (43%) or alkylating agents (42%). HVS in NDMM patients had dismal overall survival matched to multiple myeloma patient controls (without HVS) in our center (median: 3.6 vs. 7.7 years, p=0.01), as confirmed by multivariate analysis. Early deaths (in the first two months) occurred in 21% of older patients (>65 years). HVS in NDMM patients is a rare but life-threatening complication associated with high lethality in older patients and be a potential dismal prognosis factor in the modern treatment era., Competing Interests: AB received support from OCTAPHARMA for attending a meeting. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Debureaux, Harel, Parquet, Lemiale, Siguret, Goubeau, Morin, Royer, Cuccuini, Elessa, Theves, Brignier, Azoulay, Arnulf and Talbot.)

Primary effusion lymphoma (PEL) is associated with human herpesvirus 8 and frequently with Epstein-Barr virus (EBV). We report here a single-center series of 19 human immunodeficiency virus-associated PELs, including 14 EBV+ and 5 EBV- PELs. The objectives were to describe the clinicopathologic features of PELs, with a focus on programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) expression, to search for genetic alterations by targeted deep sequencing analysis, and to compare the features between EBV+ and EBV- cases. All the patients were male, and the median age at diagnosis was 47 years old (interquartile range: 40 to 56 y). Reflecting the terminal B-cell differentiation, immunophenotypic profiles showed low expression levels of B-cell markers, including CD19 (0/19), CD20 (1/19), CD79a (0/19), PAX5 (1/19), BOB1 (3/19), and OCT2 (4/19), contrasting with a common expression of CD38 (10/19), CD138 (7/19), and IRF4/MUM1 (18/19). We observed a frequent aberrant expression of T-cell markers, especially CD3 (10/19), and less frequently CD2 (2/19), CD4 (3/19), CD5 (1/19), and CD8 (0/19). Only 2 cases were PD-L1 positive on tumor cells and none PD-1 positive. With respect to immune cells, 3 samples tested positive for PD-L1 and 5 for PD-1. Our 36-gene lymphopanel revealed 7 distinct variants in 5/10 PELs, with either a single or 2 mutations per sample: B2M (n=2), CD58 (n=1), EP300 (n=1), TNFAIP3 (n=1), ARID1A (n=1), and TP53 (n=1). Finally, we did not observe any major clinical, pathologic, or immunohistochemical differences between EBV+ and EBV- PELs and the outcome was similar (2-y overall survival probability of 61.9% [95% confidence interval, 31.2-82.1] vs. 60.0% [95% confidence interval, 12.6-88.2], respectively, P=0.62)., Competing Interests: Conflicts of Interest and Source of Funding: Supported by institutional grants from INSERM and the Institut Carnot CALYM. The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Thrombocytopenia-absent radius (TAR) syndrome is a rare inherited bone marrow failure syndrome not generally associated with acute leukemia. The authors report a case of T-cell acute lymphoblastic leukemia in an adult female individual newly diagnosed with TAR syndrome. A 347-kb microdeletion of chromosome 1q21.1 involving the RBM8A gene was detected within a gain of whole chromosome 1. Next-generation sequencing on fibroblasts confirmed germline heterozygous deletion of RBM8A but on the other allele, noncoding low-frequency regulatory single-nucleotide polymorphism of RBM8A (rs139428292; rs201779890) were not found. The tolerance of the treatment was unusual and mostly marked by a slow hematopoietic recovery leading to a 6-month delay at the beginning of the maintenance phase. Only 5 cases of acute leukemia were reported in patients with TAR syndrome in the literature: 4 acute myeloid leukemia and one B-cell acute lymphoblastic leukemia. This is the first report of T-cell acute lymphoid leukemia occurring in the context of TAR syndrome., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.)

Pediatric acute myeloid leukemia is a rare and heterogeneous disease in relation to morphology, immunophenotyping, germline and somatic cytogenetic and genetic abnormalities. Over recent decades, outcomes have greatly improved, although survival rates remain around 70% and the relapse rate is high, at around 30%. Cytogenetics is an important factor for diagnosis and indication of prognosis. The main cytogenetic abnormalities are referenced in the current WHO classification of acute myeloid leukemia, where there is an indication for risk-adapted therapy. The aim of this article is to provide an updated review of cytogenetics in pediatric AML, describing well-known WHO entities, as well as new subgroups and germline mutations with therapeutic implications. We describe the main chromosomal abnormalities, their frequency according to age and AML subtypes, and their prognostic relevance within current therapeutic protocols. We focus on de novo AML and on cytogenetic diagnosis, including the practical difficulties encountered, based on the most recent hematological and cytogenetic recommendations.