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FLT3-ITD Induces CMTM6 and Enhances Immune Escape in Acute Myeloid Leukemia.

UNLABELLED: FMS-like tyrosine kinase-3 internal tandem duplication (FLT3-ITD) mutations are frequent in acute myeloid leukemia (AML) and are associated with a high risk of relapse. CKLF-like MARVEL transmembrane domain containing member 6 (CMTM6) stabilizes PD-L1 surface expression and modulates tumor immunity in solid cancer. In this study, we found a role for FLT3-induced CMTM6 in hematologic malignancies. FLT3 drove CMTM6 and PD-L1 expression in AML cells, whereas FLT3 inhibition reduced expression of CMTM6 and PD-L1. In three distinct allogeneic hematopoietic cell transplantation mouse models, transplantation of Cmtm6-deficient FLT3-ITD+ leukemia cells resulted in prolonged survival, reduced leukemia burden, enhanced T-cell effector function, and decreased expression of T-cell exhaustion markers compared with Cmtm6-proficient FLT3-ITD+ leukemia cells. Furthermore, combination therapy with anti-PD-L1 and tandutinib significantly improved survival, suppressed leukemia cell expansion, and augmented the anti-leukemia T-cell response in mice bearing FLT3-ITD+ leukemia. Mechanistically, protein-protein interaction of FLT3 and CMTM6 within their transmembrane domains, which was not phosphorylation dependent, enhanced CMTM6 stability in leukemia cells, whereas FLT3-ITD did not increase CMTM6 and PD-L1 expression at the RNA level. Furthermore, CMTM6 upregulation and protein interaction with FLT3 were validated in primary leukemia cells from two independent cohorts of patients with FLT3-ITD+ AML. Collectively, these findings uncover FLT3-mediated stabilization of CMTM6 in AML cells, which results in enhanced PD-L1 cell surface expression and leukemia immune escape. SIGNIFICANCE: Activation of the CMTM6/PD-L1 axis in FLT3-ITD-driven acute myeloid leukemia mediates immunosuppression, providing the basis for potential inhibition of this pathway to harness antitumor immunity.

Animals

Day + 30 detection of minimal residual FLT3-ITD by high-sensitivity PCR-NGS predicts relapse risk and guides post-transplant maintenance in AML.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has improved outcomes in patients with acute myeloid leukemia (AML) harboring FLT3-internal tandem duplication (FLT3-ITD) mutations. However, relapse still occurs in 15-35% of these patients after transplantation. Therefore, early and highly sensitive detection methods are required to identify patients at risk of relapse and enable timely post-transplant intervention. METHODS: In this NICHE cohort study, a total of 136 patients were included, then we evaluated whether high-sensitivity polymerase chain reaction (PCR)-next-generation sequencing (NGS) for FLT3-ITD (limit of detection: 5 × 10-6) on day + 30 post-HSCT could identify patients at a high risk of relapse and inform decisions regarding maintenance therapy. RESULTS: Among the 136 patients, 37 patients (27.2%) had detectable FLT3-ITD clones on day + 30. These patients exhibited a significantly higher cumulative incidence of post-HSCT multiparameter flow cytometry (MFC)-measurable residual disease (MRD) relapse (40.3% vs. 18.8%, p = 0.001). Notably, FLT3-ITD-positive patients who received FLT3 inhibitor maintenance therapy had no relapses, while 6 out of the 13 patients who did not receive maintenance therapy relapsed. Conversely, FLT3-ITD-negative patients without high-risk factors (2022 European LeukemiaNet adverse-risk group, relapsed/refractory AML, MFC-MRD positivity pre-HSCT) showed limited benefit from maintenance therapy (MFC-MRD-free survival: hazard ratio (HR) = 0.25 (0.03-2.11), p = 0.204; OS: HR = 0.20 (0.02-1.70), p = 0.142). CONCLUSIONS: This is the first study to demonstrate that detection of minimal FLT3-ITD clones at the fixed time point of day + 30 post-HSCT can reliably stratify relapse risk in AML patients and provide a rationale for individualized post-transplant maintenance therapy.

Humans

Expression of the FMS/KIT-like gene FLT3 in human acute leukemias of the myeloid and lymphoid lineages.

FLT3, a receptor belonging to the FMS/KIT family and localized to 13q12, could play a role in the biology of early hematopoietic progenitor cells. Because FMS and KIT are expressed in both normal progenitors and myeloid leukemias, we looked for FLT3 expression in fresh human leukemic cells using Northern blot analysis. High levels of FLT3 expression were detected in 92% of the cases of acute myeloid leukemia (AML) tested, ranging from the M1 to the M5 stages of differentiation assessed in the French-American-British classification. Immature (MO) AML cells, biphenotypic leukemias, and AML with megakaryocytic differentiation (M7 subtype) also expressed the FLT3 transcript. FLT3 was also expressed at high levels in acute lymphoid leukemias of T and B origins. Finally, it was not expressed in chronic myeloid leukemias in chronic phase, whereas it was expressed in most blast crisis samples. This pattern of expression of FLT3 contrasts with the expression of FMS and KIT restricted to myeloid leukemias, and suggests that the FLT3 product could play a role in the expansion of the leukemic blasts of both the myeloid and lymphoid lineages.

B-Lymphocytes

KIT and FLT3-ITD mutations do not predict outcomes in pediatric core-binding factor acute myeloid leukemia: findings from the C-HUANAN-AML-15 multicenter cohort study.

Although core-binding factor acute myeloid leukemia (CBF-AML) is generally considered a favorable-risk subtype in children, disease relapse remains a significant concern. The prognostic relevance of co-occurring mutations, particularly KIT and FLT3-ITD, remains debatable, and treatment intensity may modulate their impact. This multicenter analysis included 289 children (<&#x2009;14 years) with newly diagnosed CBF-AML enrolled in the C-HUANAN-AML-15 study (2015-2023). KIT and FLT3-ITD mutations were identified via cytogenetic analysis and targeted sequencing. Measurable residual disease (MRD) was evaluated by multiparameter flow cytometry (MFC) and quantitative polymerase chain reaction (PCR) following induction chemotherapy. Survival analyses were performed using Kaplan-Meier and Cox regression methods. This multicenter analysis included 289 children (<&#x2009;14 years) with newly diagnosed CBF-AML enrolled in the C-HUANAN-AML-15 study (2015-2023). KIT and FLT3-ITD mutations were identified via cytogenetic analysis and targeted sequencing. Measurable residual disease (MRD) was evaluated by multiparameter flow cytometry (MFC) and quantitative polymerase chain reaction (PCR) following induction chemotherapy. Survival analyses were performed using Kaplan-Meier and Cox regression methods. KIT mutations were detected in 103 patients (35.6%), predominantly involving exon 17 (69.9%), and were associated with extramedullary disease, sex chromosome loss, and trisomy 22. No significant differences in 5-year event-free survival (EFS), overall survival (OS), or cumulative incidence of relapse (CIR) were observed between patients with and without KIT mutations. FLT3-ITD mutations (5.5% of patients) did not adversely affect outcomes. Neither mutation independently predicted survival. MRD positivity (MFC-MRD&#x2009;&#x2265;&#x2009;0.1%) after the second induction cycle strongly predicted inferior EFS and OS and higher CIR, with corresponding results observed for molecular MRD and parallel findings for PCR-based MRD. In this large multicenter cohort, KIT and FLT3-ITD mutations did not adversely affect the prognosis of pediatric CBF-AML treated according to the C-HUANAN-AML-15 protocol. MRD after induction was the most powerful predictor of relapse and survival, underscoring its importance for risk stratification in future pediatric AML trials.

Humans

Targeting oncogenic FLT3 uncovers a ferroptosis vulnerability through selenocysteine recoding in acute myeloid leukaemia.

Ferroptosis, an iron-dependent form of cell death driven by lipid peroxidation, has emerged as a potential therapeutic strategy for therapy-resistant cancers. Glutathione peroxidase 4 and the selenoprotein biosynthesis pathway essential for its translation are key regulators of ferroptosis but lack effective therapeutic targeting. In a drug screening using a selenoprotein translation reporter, here we identify FMS-like tyrosine kinase 3 (FLT3) inhibitors as suppressors of selenoprotein translation that induce ferroptosis in FLT3-mutant acute myeloid leukaemia. Mechanistically, FLT3 inhibition disrupts selenocysteine recoding, in which a UGA stop codon is recoded as selenocysteine via the SECIS element and associated binding proteins. Notably, the antileukemic efficacy of the FLT3 inhibitor gilteritinib was markedly reduced by dietary vitamin E, which attenuated ferroptosis. This study highlights ferroptosis as a vulnerability in FLT3-mutant acute myeloid leukaemia and suggests that high vitamin E intake may compromise tyrosine kinase inhibitor efficacy partly by suppressing ferroptosis.

Ferroptosis

RUNX1A isoform is overexpressed in acute myeloid leukemia and is associated with FLT3 internal tandem duplications.

RUNX1A is the shortest and least expressed of the RUNX1 three main isoforms (A, B, C); despite this, the leukemogenic role of its overexpression has been clearly described. Several studies have shown RUNX1A involvement in different blood cancers and pilot observations in acute leukemia have been reported. In this context, we evaluated RUNX1 isoforms expression in a cohort of acute myeloid leukemia (AML) patients, finding overexpression of RUNX1A and RUNX1B, with higher median levels in thrombocytopenic cases. No difference was observed for RUNX1C. RUNX1A overexpression is higher in more immature AML phenotypes. According to the mutational profile, FLT3 internal tandem duplication (ITD) positive cases have the highest RUNX1A levels and the presence of FLT3-ITD was the only molecular variable able to influence RUNX1A expression. RUNX1A overexpression is disease-related, associated with a specific transcriptional profile, and reappears at relapse, with no clear kinetics except in FLT3-ITD cases. Overall, we demonstrate RUNX1A overexpression in AML and its association with the FLT3-ITD molecular subtype. Our data shed light on the dark side of RUNX1 deregulation, paving the way for further investigations.

Humans

Murine Flt3, a gene encoding a novel tyrosine kinase receptor of the PDGFR/CSF1R family.

Receptor-type tyrosine kinases presenting an extracellular region with five immunoglobulin-like domains, and strongly related by sequence similarities in the intracellular region, constitute a family of receptors involved in development and function of various cell lineages. We have isolated and characterized the mouse Flt3 gene, encoding the sixth member of this family. The Flt3 gene possesses an open reading frame of 3000 nucleotides, and therefore appears to code for a protein of 1000 amino acids. The deduced structure of the FLT3 protein presents all the characteristics of a receptor-type kinase of this family. The gene is expressed in placenta, in various adult tissues including gonads and brain, and in hematopoietic cells. The Flt3 transcript is 3.7 kb long, except in the testis, where two shorter post-meiotic transcripts are detected. These results suggest a role for this novel receptor and its yet unidentified ligand in placenta, gonads and hematopoietic and nervous systems.

Amino Acid Sequence

Quizartinib for patients with newly diagnosed FLT3-ITD-positive AML who received maintenance therapy in QuANTUM-First.

QuANTUM-First demonstrated improved overall survival (OS) in patients with newly diagnosed acute myeloid leukemia with FMS-like receptor tyrosine kinase 3-internal tandem duplication (FLT3-ITD) treated with quizartinib + standard chemotherapy. Herein, we evaluated the impact of postconsolidation/posttransplant single-agent maintenance therapy on clinical outcomes in patients receiving maintenance, focusing on measurable residual disease (MRD) status at maintenance onset. OS, event-free survival, and relapse-free survival were prespecified exploratory analyses. Cumulative incidence of relapse, analyses by allogeneic hematopoietic cell transplant (allo-HCT), and analyses by MRD status were post hoc and not powered for statistical significance. Samples for FLT3-ITD MRD analysis were collected from patients with composite complete remission &#x2264;30 days before receiving maintenance and assessed using an ultrasensitive amplicon-based assay. More patients who had received an allo-HCT and quizartinib treatment received maintenance (71%) vs placebo (55%); OS benefit was not demonstrated among these patients. In patients who did not undergo allo-HCT, quizartinib maintenance was associated with a significant OS benefit (hazard ratio [HR], 0.401; 95% confidence interval [CI], 0.192-0.838), including a benefit in patients who were MRD negative at the start of maintenance (OS HR, 0.194; 95% CI, 0.056-0.676). Patients who were MRD negative at the completion of consolidation achieved 89.1% (95% CI, 70.0-96.4) survival at 3 years with quizartinib maintenance in the absence of allo-HCT. These data suggest that for patients who achieve FLT3-ITD MRD negativity after induction and consolidation with quizartinib, maintenance with quizartinib provides a significant survival benefit and, in some patients, may eliminate the need for allo-HCT. This trial was registered at www.clinicaltrials.gov as NCT02668653.

Humans

Isolation and chromosomal localization of a novel FMS-like tyrosine kinase gene.

We have isolated and sequenced part of a new gene of the tyrosine kinase family. This gene, called FLT3, has strong sequence similarities with members of a group of genes encoding growth factor receptors: FMS, KIT, and PDGFR. We have localized the human FLT3 gene to chromosome 13, band q12, and its mouse homolog to chromosome 5, region G.

Amino Acid Sequence

Chromosomal localization of FLT4, a novel receptor-type tyrosine kinase gene.

A new human gene encoding a putative receptor-type tyrosine kinase (RTK) was isolated by screening a placenta cDNA library with a mouse Flt3 probe. The deduced amino acid sequence of the intracellular region of the molecule showed that it was strongly related to the FLT1 and KDR/FLK1 gene products and to a lesser degree to members of the class III RTKs: FMS/CSF1R, PDGFRA/B, KIT, and FLT3. The gene was named FLT4. Cosmid clones of the mouse Flt4 gene were isolated. The human gene was localized to bands q34-q35 of chromosome 5, i.e., slightly telomeric to the CSF1R/PDGRFB tandem of genes, and the mouse homolog to chromosome 11, region A5-B1.

Amino Acid Sequence

Mutational Landscape and Clonal Dynamics in AML Undergoing PTCy Hematopoietic Cell Transplantation.

To improve risk stratification, we performed targeted NGS at diagnosis in 191 patients with AML undergoing myeloablative allogeneic HCT with PTCy-based prophylaxis. We also investigated clonal evolution using paired diagnostic and relapse samples from 39 individuals. A total of 610 mutations were detected in 184 patients (96%), most commonly in FLT3 (26%), DNMT3A (25%), RUNX1 (24%), and NPM1 (19%). Sixteen unique fusion genes were identified in 35 patients, with KMT2A (43%) and core binding factor rearrangements (23%) being the most frequent. TP53 and WT1 mutations were strongly associated with adverse outcomes, whereas NPM1 retained favorable significance. RUNX1 co-mutations with SF3B1 or NRAS were associated with inferior survival. In an exploratory allelic analysis, multi-hit TP53 alterations, but not single-hit mutations, were associated with distinctly poorer OS, EFS, and relapse risk. Relapse involved mutational shifts in &#x223c;70% of cases, with significant enrichment of WT1 and more modest increases in TP53, KRAS, ASXL1, NF1, and MECOM, while DNMT3A, TET2, and ASXL1 persisted stably. Neither acute nor chronic graft-versus-host disease was associated with molecular remodeling at relapse. Incorporating TP53 and WT1 into risk models, recognizing context-dependent effects of DNMT3A and RUNX1, and applying longitudinal genomic monitoring may help guide personalized strategies to prevent relapse. Extended abstract BACKGROUND Relapse remains the leading cause of treatment failure after allogeneic hematopoietic cell transplantation (HCT) for acute myeloid leukemia (AML), yet the genetic mechanisms underlying post-transplant relapse remain poorly understood, particularly in the era of post-transplant cyclophosphamide (PTCy). Characterizing the mutational landscape at diagnosis and the clonal evolution leading to relapse may improve post-transplant risk stratification and identify opportunities for personalized surveillance and intervention. OBJECTIVES To characterize the diagnostic mutational landscape, evaluate its prognostic significance, and investigate clonal evolution from diagnosis to relapse in AML patients undergoing myeloablative HCT with PTCy-based graft-versus-host disease prophylaxis. STUDY DESIGN We performed targeted next-generation sequencing (NGS) at diagnosis in 191 consecutive AML patients undergoing myeloablative allogeneic HCT with PTCy-based prophylaxis. Paired diagnostic and relapse samples were available for 39 patients to evaluate clonal evolution. RESULTS A total of 610 mutations were detected in 184 patients (96%), most commonly in FLT3 (26%), DNMT3A (25%), RUNX1 (24%), and NPM1 (19%). Sixteen unique fusion genes were identified in 35 patients, with KMT2A (43%) and core binding factor rearrangements (23%) being the most frequent. TP53 and WT1 mutations were strongly associated with adverse outcomes, whereas NPM1 retained favorable significance. RUNX1 co-mutations with SF3B1 or NRAS were associated with inferior survival. In an exploratory allelic analysis, multi-hit TP53 alterations, but not single-hit mutations, were associated with distinctly poorer OS, EFS, and relapse risk. Relapse involved mutational shifts in &#x223c;70% of cases, with significant enrichment of WT1 and more modest increases in TP53, KRAS, ASXL1, NF1, and MECOM, while DNMT3A, TET2, and ASXL1 persisted stably. Neither acute nor chronic graft-versus-host disease was associated with molecular remodeling at relapse. CONCLUSIONS This study provides a comprehensive characterization of the mutational landscape and clonal evolution of AML undergoing contemporary PTCy-based allogeneic HCT. TP53 and WT1 identify patients at particularly high risk of post-transplant relapse, whereas NPM1 retains favorable prognostic significance. The frequent acquisition of new genetic lesions at relapse underscores the dynamic nature of post-transplant clonal evolution and supports longitudinal molecular monitoring together with genomically informed post-transplant surveillance and relapse-prevention strategies.

Clonal Dynamics

Targeted Therapy in Acute Myeloid Leukemia: Current Approaches and Novel Directions.

Acute myeloid leukemia (AML) is a molecularly heterogeneous neoplasm of hematopoietic stem and progenitor cells. The advent of high-resolution genomic sequencing has uncovered several genetic drivers of AML which spurred a surge of therapies that target the disease at a mutational, clonal, or epigenetic level. Currently, the molecular profiling of AML patients before treatment is commonplace and crucial for ensuring that patients receive the most optimal therapy for any driver mutations they may have. Here, we detail the current targeted therapies available for AML: specifically, those targeting the BCL2 family (venetoclax), FLT3 (midostaurin, gilteritinib, quizartinib), IDH1/2 (enasidenib, ivosidenib), and MENIN (revumenib, ziftomenib). In addition, we outline potential mechanisms of resistance against these therapies, as well as efforts being taken to prevent or bypass them.

BCL2

The Germline SH2B3rs111340708 Splicing Variant Drives Intron Retention and Protein Instability by Impacting Clinical Outcomes in Core Binding Factor AML.

The SH2B3 gene, also known as LNK, encodes an adaptor protein that negatively regulates key hematopoietic signaling pathways, including JAK-STAT, MAPK, and PI3K/AKT, thereby maintaining hematopoietic homeostasis. SH2B3 interacts with major signaling regulators such as JAK2, MPL, FLT3, and KIT. Loss-of-function alterations have been reported in several hematologic malignancies, supporting its role as a leukemia predisposition gene. We previously identified a germline start-loss mutation (c.3G&#xa0;>&#xa0;A) in SH2B3 in a family with early-onset myeloproliferative neoplasm, demonstrating that this variant causes SH2B3 haploinsufficiency. In the present study, next-generation sequencing of 149 de novo AML patients identified a frequent intronic polymorphism (rs111340708), located within intron 6 (IVS6) of SH2B3. Although this variant has a reported minor allele frequency (MAF) of approximately 12% in European populations, it was enriched in our AML cohort, reaching 34.2% in Core Binding Factor leukemias (CBFLs). The presence of the rs111340708 variant was associated with inferior overall survival, whereas no significant association with progression-free survival was observed. Functional analyses demonstrated that this polymorphism promotes aberrant IVS6 intron retention in AML cells, resulting in reduced abundance of correctly spliced SH2B3 transcripts and predicted generation of truncated peptides and/or nonsense-mediated decay. Consistently, immunoblot analyses of AML patient samples and hematologic cell lines revealed heterogeneous SH2B3 protein expression, including additional SH2B3-immunoreactive species in variant carriers, together with reduced levels of the canonical SH2B3 protein. Collectively, these findings identify a common germline splicing polymorphism as a novel mechanism contributing to SH2B3 functional impairment in AML and highlight the potential relevance of non-coding variants in leukemia pathogenesis, with possible implications for risk stratification and future therapeutic strategies.

Humans

Acute leukemia therapy at a crossroads: from conventional chemotherapy to the era of precision medicine.

Since the discovery of cytotoxic agents in the mid-20th century, acute leukemia has consistently served as a model for oncology research. As the Human Genome Project and subsequent genomic profiling elucidated the landscape of somatic mutations and cytogenetic aberrations driving leukemogenesis, the development of molecularly targeted therapies has dramatically accelerated, yielding significant improvements in patient outcomes. In acute myeloid leukemia (AML), the emergence of selective inhibitors targeting high-frequency alterations such as FLT3, NPM1, and IDH1/2 has redefined the standard of care, demonstrating superior efficacy when combined with conventional intensive chemotherapy or hypomethylating agents. Simultaneously, for acute lymphoblastic leukemia (ALL), in addition to the significant improvements achieved by tyrosine kinase inhibitors (TKIs) for BCR-ABL-positive ALL, the advent of CD19- or CD22-targeted monoclonal antibodies and CAR-T cell therapies has marked an epoch-making milestone, representing a major paradigm shift in the management of relapsed or refractory cases. Bridging these two distinct lineages, menin inhibitors have emerged as a novel class of agents targeting a common pathogenic mechanism in KMT2A-rearranged AML/ALL and NPM1-mutated AML, exhibiting promising antileukemic activity across these subtypes. In this review, we describe the evolution of leukemia therapy-highlighting historical trajectory across AML, APL, and ALL from uniform cytotoxic chemotherapy to molecularly targeted agents, antibody-based therapies, and chemo-free paradigms, while outlining future perspectives for precision hematology.

Acute lymphoblastic leukemia

Genetic Profile, Treatment Response, and Outcomes of BCR::ABL1-Positive Mixed-Phenotype Acute Leukemia: A Study From the BCR::ABL1 Pathology Group.

Mixed-phenotype acute leukemia (MPAL) with BCR::ABL1 fusion is rare, and its clinicopathological features, genetic landscape, therapeutic response, and patient outcomes remain incompletely defined, as does its relationship to blast-phase chronic myeloid leukemia. In this multicenter study of 44 patients, 86.4% had B/myeloid MPAL, 72.7% showed lymphoid predominance, 40.9% had complex karyotypes, and 68.3% harbored somatic mutations, most commonly RUNX1 mutations (46.3%). RUNX1 mutations frequently co-occurred with acute myeloid leukemia (AML)-associated alterations, whereas DNMT3A, TET2, and BCORL1 mutations were restricted to RUNX1-mutated cases. In contrast, acute lymphoblastic leukemia (ALL)-associated alterations (IKZF1 mutation/deletion and ETV6 mutations) were confined to RUNX1-wild-type patients. TP53 and signaling pathway mutations (NRAS, KRAS, PTPN11, and FLT3) were not detected. Forty-two patients received induction chemotherapy and/or immunotherapy combined with tyrosine kinase inhibitors: 74.2% of lymphoid-predominant patients and 63.6% of myeloid-predominant patients received ALL- and AML-type therapies, respectively. Ten patients relapsed, and 2 had primary refractory disease; some exhibited a dynamic shift in predominant lineage immunophenotype, chromosomal alterations, and somatic mutations at the relapse or refractory stage. The overall remission rate was 86.8%, with no significant differences across ALL-, AML-, or hybrid-type regimens. After a median follow-up of 24.2 months, the median overall survival was 52.5 months. Complex karyotype was associated with inferior overall survival compared with cases lacking additional chromosomal alterations (P = .02), whereas RUNX1 mutations were not. No significant differences in genetic profiles, treatment response, or outcomes were observed between patients with and without chronic myeloid leukemia-like features. This study provides a comprehensive genomic and clinical characterization of BCR::ABL1-positive MPAL, supporting improved risk stratification and future therapeutic strategies.

Adolescent

Azacitidine-Venetoclax or Induction Chemotherapy for Acute Myeloid Leukemia.

BACKGROUND: Induction chemotherapy has long been a key component of curative therapy for fit patients with acute myeloid leukemia (AML), despite its frequently severe side effects and substantial health care utilization. For patients who are ineligible for induction chemotherapy, hypomethylating therapy plus venetoclax is the standard treatment owing to its efficacy and side-effect profile. METHODS: In this multicenter, phase 2 trial, we randomly assigned, in a 1:1 ratio, previously untreated adults with AML who were eligible for induction chemotherapy to receive either azacitidine plus venetoclax or induction chemotherapy. Patients with core binding factor fusions, mutations in the gene encoding FMS-like tyrosine kinase 3 (FLT3), or mutations in the gene encoding nucleophosmin-1 (NPM1; unless the patient was &#x2265;60 years of age) were excluded. The primary end point was event-free survival. RESULTS: A total of 172 patients underwent randomization, with 86 patients assigned to each group. The median age of the patients was 64 years. A total of 72% of the patients had adverse-risk disease according to the European LeukemiaNet 2022 classification. At a median follow-up of 21.9 months, the median event-free survival was 14.5 months (95% confidence interval [CI], 10.4 to 24.4) in the azacitidine-venetoclax group, as compared with 6.2 months (95% CI, 4.1 to 10.1) in the induction chemotherapy group, corresponding to a hazard ratio for event or death of 0.57 (95% CI, 0.39 to 0.84; P&#x2009;=&#x2009;0.002 by the stratified log-rank test). Infection of grade 3 or higher occurred in 28% of the patients (95% CI, 19 to 39) receiving azacitidine-venetoclax and in 41% of those (95% CI, 30 to 52) receiving induction chemotherapy; hemorrhage of grade 3 or higher occurred in 2% (95% CI, 0.3 to 8) and 12% (95% CI, 6 to 20), respectively. CONCLUSIONS: In this phase 2, randomized trial, azacitidine-venetoclax therapy led to significantly longer event-free survival than induction chemotherapy among induction-eligible patients with AML. (Funded by AbbVie and others; PARADIGM ClinicalTrials.gov number, NCT04801797.).

Adult

Epigenetics and In Silico Transcriptome Analysis of Pediatric Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy that accounts for about 15%-20% of childhood leukemias. Despite therapeutic advances, relapses remain common, and survival for high-risk patients is below 60%. Unlike adult AML, pediatric AML displays distinct genetic mutations, including FLT3-ITD, NPM1, KMT2A rearrangements, and core-binding factors (CBF) fusions, as well as extensive epigenetic dysregulation. Aberrant DNA methylation, histone modifications, and altered non-coding RNA expressions disrupt hematopoietic differentiation and activate oncogenic transcriptional networks. Recent advances in silico transcriptomic analysis have transformed the study of pediatric AML by integrating gene expression and epigenetic data to identify molecular drivers and regulatory networks. Computational RNA-seq pipelines and pathway analyses have highlighted key epigenetic regulators, including DNMT3A, TET2, and HDACs, as potential therapeutic targets. Multi-omics approaches combining transcriptomic, methylomic, and chromatin accessibility data are increasingly used to define biomarkers for diagnosis, prognosis, and therapeutic response. This review provides a comprehensive overview of the molecular and epigenetic landscape of pediatric AML, emphasizing the power of in silico transcriptome analysis to uncover disease mechanisms, refine patient stratification, and guide the development of precision-based epigenetic therapies aimed at improving long-term outcomes in children with AML.

Humans

Germline noncoding risk variants influence clonal hematopoiesis through altered hematopoietic enhancer activity.

Clonal hematopoiesis of indeterminate potential (CHIP) is a precursor condition characterized by the expansion of mutant hematopoietic stem and progenitor cell (HSPC) clones that increases the risk of hematologic malignancies. Although genome-wide association studies have identified multiple non-coding loci associated with CHIP susceptibility, their mechanisms remain unclear. We hypothesized that CHIP risk variants alter enhancer activity in HSPCs. To test this, we screened 1,374 non-coding variants from 51 CHIP-associated loci using a Massively Parallel Reporter Assay (MPRA) in the CD34+ fraction of MUTZ-3 cells. We identified 87 regulatory variants across 32 loci. Targeted genome editing in hematopoietic cells and complementary reporter assays in primary human HSPCs validated enhancer activity for variants regulating NKD2, FLT3, and MSI2. Functional studies demonstrated that increased MSI2 expression, modeling the effect of the CHIP risk allele, promotes clonal expansion of TET2-deficient HSPCs, providing a mechanistic link between inherited non-coding variation and CHIP clonal expansion.

Journal Article