EZH2 Mutations Are Associated with Low Blast Percentage in Bone Marrow and −7/Del(7q) Karyotype in De Novo Acute Myeloid Leukemia.

Abstract 2544

Somatic mutation of the EZH2 gene is seen in myelodisplastic syndrome, myelofibrosis, and chronic myelomonocytic leukemia patients. The prevalence and prognostic impact of somatic mutations of EZH2 in patients with acute myelogenous leukemia (AML) remains unknown. In this study, we sought to determine the incidence and clinical implications of somatic EZH2 mutations in 714 patients with de novo AML by PCR amplification of the entire coding region followed by direct bidirectional DNA sequencing. EZH2 mutations were identified in 13/714 (1.8%) of AML patients and occurred almost exclusively in males (11/13, P=0.033). In univariate analysis, the presence of EZH2 mutations was significantly associated with lower blast percentage (21–30%) in bone marrow (P=0.0001) and −7/del(7q) (P=0.025). There was no difference in the incidence of mutations in 13 genes, including ASXL1, CBL, c-KIT, DNMT3A, FLT3, IDH1, IDH2, MLL, NPM1, NRAS, RUNX1, TET2, and WT1, between patients with and without EZH2 mutations. Complete remission, event-free survival or overall survival was similar between AML patients with and without EZH2 mutation (p>0.05). These results demonstrated EZH2 mutation as a recurrent genetic abnormality associated with lower blast percentage in BM and −7/del(7q) in de novo acute myeloid leukemia.