FLT3/internal tandem duplication subclones in acute myeloid leukemia differ in their engraftment potential in NOD/SCID mice.

In this study, we tested if FLT3/internal tandem duplication (ITD) in acute myeloid leukemia (AML) might occur at different hierarchical stages during leukemogenesis. In 56 AML cases, 10 showed FLT3/ITD (single ITD=5; multiple ITD=5). Myeloblasts from seven cases (CD34-selected=4; unselected=3) were transplanted into NOD/SCID mice. Five cases engrafted successfully into 14 mice. Two patients carried single FLT3/ITD subclones, which were maintained during primary and secondary transplantations. In three patients with multiple FLT3/ITD subclones, some subclones persisted or expanded while others diminished upon transplantation. Their different engraftment capabilities in NOD/SCID mice supported the proposition that FLT3/ITD might occur at different stages during leukemogenesis. 2009 Elsevier Ltd. All rights reserved.