Genomic landscapes of 92 adult and 111 pediatric patients with B-cell acute lymphoblastic leukemia (B-ALL) were investigated using next-generation sequencing and copy number alteration analysis. Recurrent gene mutations and fusions were tested in an additional 87 adult and 93 pediatric patients. Among the 29 newly identified in-frame gene fusions, those involving MEF2D and ZNF384 were clinically relevant and were demonstrated to perturb B-cell differentiation, with EP300-ZNF384 inducing leukemia in mice. Eight gene expression subgroups associated with characteristic genetic abnormalities were identified, including leukemia with MEF2D and ZNF384 fusions in two distinct clusters. In subgroup G4 which was characterized by ERG deletion, DUX4-IGH fusion was detected in most cases. This comprehensive dataset allowed us to compare the features of molecular pathogenesis between adult and pediatric B-ALL and to identify signatures possibly related to the inferior outcome of adults to that of children. We found that, besides the known discrepancies in frequencies of prognostic markers, adult patients had more cooperative mutations and greater enrichment for alterations of epigenetic modifiers and genes linked to B-cell development, suggesting difference in the target cells of transformation between adult and pediatric patients and may explain in part the disparity in their responses to treatment.

Natural killer/T-cell lymphoma (NKTCL) is a malignant proliferation of CD56(+) and cytoCD3(+) lymphocytes with aggressive clinical course, which is prevalent in Asian and South American populations. The molecular pathogenesis of NKTCL has largely remained elusive. We identified somatic gene mutations in 25 people with NKTCL by whole-exome sequencing and confirmed them in an extended validation group of 80 people by targeted sequencing. Recurrent mutations were most frequently located in the RNA helicase gene DDX3X (21/105 subjects, 20.0%), tumor suppressors (TP53 and MGA), JAK-STAT-pathway molecules (STAT3 and STAT5B) and epigenetic modifiers (MLL2, ARID1A, EP300 and ASXL3). As compared to wild-type protein, DDX3X mutants exhibited decreased RNA-unwinding activity, loss of suppressive effects on cell-cycle progression in NK cells and transcriptional activation of NF-κB and MAPK pathways. Clinically, patients with DDX3X mutations presented a poor prognosis. Our work thus contributes to the understanding of the disease mechanism of NKTCL.

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Purpose: Mantle-cell lymphoma (MCL) is an incurable mature B-cell neoplasm with high initial response rates followed almost invariably by relapse. Prognosis for patients following relapse is poor, and treatment choices are limited. We evaluated the efficacy and safety of zanubrutinib, an investigational selective Bruton's tyrosine kinase (BTK) inhibitor. Patients and Methods: Patients with relapsed/refractory MCL were enrolled in this ongoing phase II, single-arm, open-label study, and treated with oral zanubrutinib 160 mg twice daily. The primary endpoint is overall response rate (ORR) assessed by an independent review committee (per Lugano 2014 classification); secondary endpoints include duration of response (DOR), time to response, progression-free survival (PFS), and safety. Results: Eighty-six patients (median age, 60.5 years) were enrolled after a median of 2 prior lines of therapy, received ≥1 dose of the study drug, and were evaluable for safety and efficacy. After a median follow-up of 18.4 months, 72 (84%) patients achieved an objective response, with 59 (68.6%) achieving a complete response (CR). Median DOR and PFS were 19.5 and 22.1 months, respectively; 12-month event-free estimates for DOR and PFS are 78% and 76%, respectively. Most common grade ≥3 adverse events (AE) were neutropenia (19.8%) and lung infection/ pneumonia (9.3%). Three patients experienced major bleeding events, and there were no reports of atrial fibrillation. Eight (9.3%) patients discontinued zanubrutinib for AEs. Conclusions: These results demonstrate high and durable ORR and CR rates in patients with relapsed/refractory MCL. Zanubrutinib was generally well tolerated; grade ≥3 BTK inhibitorassociated toxicities (hemorrhage, rash, hypertension, diarrhea, atrial fibrillation) were uncommon.