FLT3-ITD mutation may occur in the early phase of leukemia pathogenesis, even blast cell with FLT3-ITD mutation are eliminated by chemotherapy, the aberrant mutation that pre-existed in LSC could still play an indispensable role in the relapse of the leukemia [41–43], and our data provided new insights into the pathogenesis of LSC. This evidence concerns the gene FLT3 and leukemia.