NPM1 and FLT3-ITD/TKD Gene Mutations in Acute Myeloid Leukemia

Abstract

Background: A number of mutations have been reported to occur in patients with acute myeloid leukemia (AML), of which NPM1 and FLT3 genes mutations are the commonest and have important diagnostic and therapeutic implications.

Material and Methods: Molecular testing for NPM1 and FLT3 genes was performed in 92 de-novo AML patients. The frequency and characteristics of NPM1 and FLT3 mutations were analyzed.

Results: Nucleophosmin 1(NPM1) and FMS-like tyrosine kinase 3 (FLT3) mutations were seen in 22.8% and 16.3% of patients, respectively. Amongst FLT3 mutations, FLT3-ITD mutation was seen in 8.7% cases, FLT3- TKD in 5.4%, and FLT3-ITD+TKD in 2.2% cases. Certain associations between the gene mutations and clinical characteristics were found, including in NPM1 mutated group- female preponderance, higher incidence in M4/M5 categories and decreased expression of CD34 and HLA-DR; and in FLT3-ITD mutated group- higher age of presentation, higher total leucocyte count and blast percentage.

Conclusion- AML patients with NPM1 and FLT3 mutations have differences in clinical and hematological features, which might represent their different molecular mechanism in leukemogenesis. The frequency of NPM1 and FLT3 mutations in this study was comparable to reports from Asian countries but lower than that reported from western countries. However, as the number of patients in the study was less, a larger number of patients need to be studied to corroborate these findings.