Internal tandem duplication of FLT3 in relapsed acute myeloid leukemia: a comparative analysis of bone marrow samples from 108 adult patients at diagnosis and relapse

Analysis of internal tandem duplications of FLT3 (FLT3/ITD) was performed on bone marrow samples obtained at diagnosis and relapse from 108 adult patients with de novo acute myeloid leukemia (AML) to determine the role of this mutation in leukemic relapse. Eighty-three patients had wild-type FLT3 at both diagnosis and relapse, 16 had FLT3/ITD at both stages, whereas 8 had acquired the mutation and 1 had lost it at relapse. Using Genescan analysis, we found that FLT3/ITD levels at first relapse were significantly higher than those at diagnosis (mean +/- SE, 40.5% +/- 4.8% versus 17.9% +/- 3.6%, P