FLT3 and NPM-1 mutations in a cohort of acute promyelocytic leukemia patients from India

BACKGROUND: Acute promyelocytic leukemia (APL) with t (15;17) is a distinct category of acute myeloid leukemia (AML) and is reported to show better response to anthracyclin based chemotherapy. A favorable overall prognosis over other subtypes of AML has been reported for APL patients but still about 15% patients relapse. METHODS: This study evaluated the presence of Famus like tyrosine kinase-3 (FLT3) and nucleophosmin-1 (NPM1) gene mutations in a cohort of 40 APL patients. Bone marrow/peripheral blood samples from patients at the time of diagnosis and follow-up were processed for immunophenotyping, cytogenetic markers and isolation of DNA and RNA. Samples were screened for the presence of mutations in FLT3 and NPM1 genes using polymerase chain reaction followed by sequencing. RESULTS: Frequency of FLT3/internal tandem duplication and FLT3/tyrosine kinase domain was found to be 25% and 7% respectively. We observed a high frequency of NPM1 mutation (45%) in the present population of APL patients.