The FLT3 internal tandem duplication mutation at disease diagnosis is a negative prognostic factor in myelodysplastic syndrome patients

Abstract

The role of the FMS-like tyrosine kinase 3 (FLT3) gene in acute myeloid leukemia (AML) has been well documented and the FLT3-internal tandem duplication (FLT3-ITD) mutation has been identified as a prognostic factor in AML. Due to its low incidence, the role of the FLT3 mutation remains unclear in myelodysplastic syndrome (MDS) patients. To investigate the impact of the FLT3-ITD status on the prognosis of MDS at diagnosis, we retrospectively analyzed 72 MDS patients admitted to Teikyo University Hospital. FLT3-ITD was examined by a reverse transcription-polymerase chain reaction using complementary DNA synthesized from mRNA extracted from bone marrow mononuclear cells at the diagnosis of MDS. Fifteen patients (20.8 %) were positive for FLT3-ITD and had significantly worse overall survival (OS) and progression-free survival (PFS) than patients who were negative (P < 0.001 and P < 0.001, respectively) in a multivariate analysis. We also investigated whether the Wilms’ tumor gene-1 (WT-1) copy number was associated with the FLT3-ITD mutational status using data available on WT-1 from 57 patients. A WT-1 transcript copy number ≥50/μg total mRNA in peripheral blood was detected in 35 patients (61.4 %). All FLT3-ITD-positive patients showed WT-1 ≥50. The FLT3-ITD-positive group showed significantly higher WT-1 transcription levels than the negative group. These results indicate that the FLT3-ITD mutation has a prognostic impact at the diagnosis of MDS and is associated with a high level of WT-1.