OBJECTIVETo evaluate the prevalence and distribution of C-kit, NPM1 and FLT3 gene mutations in patients with acute myeloid leukemia (AML), and to analyze the relationship between the gene mutations and their prognosis.

METHODSMutations in exon 8 and 17 of C-kit gene, exon 12 of NPM1 gene, exon 20 of FLT3-TKD gene, and exon 14/15 of FLT3-ITD gene were detected by direct sequencing. Clinical data was collected and followed up if the patient had accepted treatment in our hospital.

RESULTSAmong the 656 AML patients, mutations in C-kit exon 8 were found in 6 patients (0.9%), C-kit exon 17 in 33 (5.0%), NPM1 in 169 (25.8%), FLT3-TKD in 46 (7.1%), and FLT3-ITD in 178 (27.1%). Six subtypes of mutations were detected in C-kit exon 8, 8 in C-kit exon 17, 11 in FLT3-TKD, 15 in NPM1, of which 5 were not reported before. C-kit exon 17 mutations were more frequently detected in patients with t(8;21) and exon 8 in patients with inv(16) cytogenetic abnormality. No other gene mutations except FLT3 were detected in M(3) patients. NPM1 and ITD mutations were often detected in individuals with normal cytogenetics or M(5) and M(1) of FAB classification, and accompanied with high white blood cell counts in peripheral blood, high blast counts in bone marrow and low CD34 expression. The older the patients were when diagnosed, the more gene mutations and the higher white blood cell count were detected. More mutations were found in individuals with normal karyotype than that with other karyotypes. It appeared that FLT3-ITD was significantly associated with shorter overall survival (OS) (P = 0.004), NPM1 was not significantly associated with OS, but NPM1(+)/ITD(-) patients had the longest OS.

CONCLUSIONSOur results showed that the mutation types and amounts had particular distribution in MICM subtypes, and were associated with white blood cell counts in peripheral blood, blast counts in bone marrow and prognosis. Especially for patients with normal karyotype, the genetic mutations could be new molecule marker.