Prevalence and prognostic significance of FLT3 gene mutations in patients with acute leukaemia: analysis of patients from the Shanghai Leukaemia Co-operative Group.

This study was designed to evaluate the prevalence of fms-like tyrosine kinase-3 (FLT3) gene mutations in the World Health Organization classified subtypes of acute leukaemia (AL), and their prognostic significance in terms of complete remission (CR), leukaemia-free survival (LFS) and overall survival (OS). Of 468 patients, 374 (79.9%) had acute myeloid leukaemia (AML) and 83 (17.7%) had acute lymphoblastic leukaemia (ALL). Among the AML patients, a FLT3 internal tandem duplication (FLT3/ITD) mutation was present in 59 cases (15.8%), whereas a FLT3/D835 mutation was detected in 15 cases (4.0%). Conversely, in the ALL patients, no FLT3/ITD mutations were detected and a FLT3/D835 mutation was found in only two cases (2.4%). The FLT3/ITD mutation was associated with a lower CR rate compared with those with no mutations (52.3% versus 71.1%) and with a shorter median OS (9 versus 18 months) in AML patients. In conclusion, the FLT3/ITD mutation occurred frequently in AML and was associated with a lower CR and shorter median OS. In contrast, FLT3/D835 mutations were not of prognostic value.