Variable prognostic value of FLT3 internal tandem duplications in patients with de novo AML and a normal karyotype, t(15;17), t(8;21) or inv(16).

Introduction: Internal tandem duplication of the FLT3 gene (FLT3/ITD) has been linked to poor outcome in acute myeloid leukemia (AML). However, the prognostic value of FLT3/ ITD in various cytogenetic risk groups is still a matter of debate. The aim of this study was to evaluate the prognostic significance in patients with de novo AML and a normal karyotype or a t(15;17), t(8;21) or inv(16) (good risk group). Patients and methods: Diagnostic samples of 100 patients were investigated by single-step PCR of exons 11 and 12 of the FLT3 gene in a single center retrospective analysis. Subgroups included 53 patients with normal karyotype, 21 patients with t(15;17), 9 patients with t(8;21) and 17 patients with inv(16). Results: FLT3/ITD was found in 26 out of 100 patients: 30% of patients with a normal karyotype and 38% of t(15;17) patients tested positive. The complete remission (CR) rates for the ITD + or ITD 7 groups were 50 vs 76% in normal karyotypes, and 100 vs 53% in t(15;17) patients, while the relapse rates were 75 vs 25% in normal karyotypes and 50 vs 42% in t(15;17) patients. Overall survival (OS) and disease free survival (DFS) at 5 years were significantly diAerent in patients with normal cytogenetics: ITD + vs ITD 7 :O S 6vs 28% (P50.003); DFS 13 vs 41% (P50.02) Interestingly, FLT3/ITD had no significant eAect on the outcome of t(15;17) patients: ITD + vs ITD 7 :O S 85vs 53% (P=0.056), DFS 45 vs 60%