The new structural chromosome changes frequently seen in AML cells with FLT3-ITD at relapse [4] are attributed at least in part to genomic instability caused by error-prone Alt-NHEJ repair of the increased DNA DSBs present in cells with FLT3-ITD [17, 18], and genomic instability is thought to contribute to relapse [4, 19]. Here, FLT3 is linked to acute myeloid leukemia.