Effect of <i>DNMT3A</i> variant allele frequency and double mutation on clinicopathologic features of patients with de novo AML
Damodaran Narayanan, Olga Pozdnyakova, Robert P. Hasserjian, Sanjay S. Patel, Olga K. Weinberg
Abstract
The clinicopathologic features of DNA methyltransferase 3A (DNMT3A)-mutated de novo acute myeloid leukemia (AML), and the significance of variant type, variant allele frequency (VAF), and multiple concomitant DNMT3A mutations, remain poorly defined. We examined 104 DNMT3A-mutated de novo AML patients from 2 major centers. Most (82%) had normal karyotype (NK); R882H variants were frequent(38%). The most commonly comutated genes included nucleophosmin (NPM1; 53%), Fms-related tyrosine kinase 3 (FLT3)-internal tandem duplication (25%), IDH1 (23%), IDH2 (23%), and TET2 (21%). Patients with high DNMT3A VAF at diagnosis (≥44%; DNMT3AHIGH) had more significant leukocytosis and higher blast counts in peripheral blood and bone marrow. DNMT3AHIGH cases were associated with much shorter event-free survival (EFS; 14.1 vs 56.8 months) and overall survival (OS; 18.3 months vs not reached) compared with cases of patients with low DNMT3A (DNMT3ALOW). Thirteen patients had 2 DNMT3A variants and similar VAFs at diagnosis that tracked together at multiple time points after chemotherapy and/or stem cell transplantation (SCT). In multivariable analyses performed in NK patients who received standard induction chemotherapy, presence of 2 DNMT3A mutations (hazard ratio [HR] = 3.192; P = .038) and SCT in first complete remission (HR = 0.295; P = .001) independently affected EFS; increasing marrow blast percentage (HR = 1.026; P = .025), high DNMT3A VAF (HR = 3.003; P = .010), and 2 DNMT3A mutations (HR = 4.816; P = .020) had independent effects on OS. These data support the adverse prognostic significance of DNMT3AHIGH reveal a novel association between 2 concomitant DNMT3A mutations and inferior outcome in DNMT3A-mutated de novo AML with a NK.