Prognostic significance of FLT3 internal tandem duplication in Egyptian acute myeloid leukemia and normal cytogenetics

Internal tandem duplication of the FLT3 gene (FLT3/ITD) has been linked to a 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 of FLT3/ITD in patients with de novo AML and normal cytogenetics (NC-AML). Diagnostic samples of 39 patients were investigated by PCR of exons 14 and 15 of the FLT3 gene in patients with AML. Subgroups included 26 patients with normal cytogenetics, 8 patients with t(15;17), 4 patients with t(8;21), and 1 patient with inv (16). FLT3/ITD was found in 6/39 (15.4%) AML cases. By cytogenetic subgroups, there were 4/6 normal cytogenetics, 1/6 t(15;17) and 1/6 t(8;21) positive patients. Patients were M1, 3/13; M2, 2/12; M3, 1/9; M4, 0/4; and M5, 0/1. The patients were followed up for a mean of 34.5 ± 2.3 months. The complete remission rates for the FLT3/ITD+ and FLT/ITD− groups were 50% vs 63.6% in normal cytogenetics, while the relapse rates were 50% vs 28.6% in normal cytogenetics. Interestingly, disease-free survival (DFS) at 3 years was significantly different in patients with normal cytogenetics: DFS was 5% in patients with FLT3/ITD+ vs 30% of patients with FLT3/ITD− (P = 0.001). Although based on a study with a limited number of AML patients, our data suggest a high prognostic value of FLT3/ITD in patients with normal/favorable cytogenetics. Further study on a larger scale is recommended.