Clinical characteristics of newly diagnosed acute myeloid leukemia patients with NPM1 mutation

Abstract

The purpose of this study was to investigate the clinical characteristics of newly diagnosed acute myeloid leukemia (AML) patients with NPM1 mutation in exon 12 and to explore the relationship between NPM1 mutation and FLT3-ITD, IDH1 mutation. The AML clinical data and bone marrow samples of patients were collected. The diagnosis and classification were based on WHO criteria. The genomic DNA was extracted and NPM1 mutation was detected by sequencing after PCR. The specimens of 389 AML patients were tested. The results showed that the NPM1 mutation was found in 14.1% samples (55/389). The incidence of FLT3-ITD mutation was 14.7% (57/389) . The incidence of IDH1 mutation was 6.4% (25/389) . NPM1 mutation was not detected in AML with AML1-ETO, PML-RARA or CBF-MYH11 fusion genes. The incidences of FLT3-ITD and IDH1 mutation were 29.1% and 12.7% respectively in AML with NPM1 mutation. The incidences of FLT3-ITD and IDH1 mutation were 12.3% and 5.4% respectively in AML without NPM1 mutation. The incidences of FLT3-ITD and IDH1 mutation were significantly higher in AML with NPM1 mutation than that in AML without NPM1 mutation. The incidence of NPM1 mutation in normal karyotype AML was 26.5% (35/132) which significantly higher than that in other AML. The AML with NPM1 mutation characterized by older age, high platelet number, higher incidence in AML-M5, lower CD34 positive cells, more possible co-existence with FLT3-ITD and IDH1 mutation and other clinical features. The complete remission rate after one cycle of induction chemotherapy was 69.8% in AML without NPM1 mutation. The complete remission rate after one cycle of induction chemotherapy was 72.2% in AML with NPM1 mutation, there was no significant difference between them (P = 0.07). It is concluded that AML with NPM1 mutation has distinct clinical features. NPM1 mutation can co-exists with FLT3-ITD and IDH1 mutation, but not with AML1-ETO, PML-RARA or CBF-MYH11 fusion genes.