FLT3 and acute myeloid leukemia: FMS-like tyrosine kinase 3 (FLT3) is widely expressed by immature hematopoietic progenitors and over-expressed in a majority of AML blasts, often in the presence of activating mutations by tandem duplications (FLT3-ITD) and/or point mutations involving the tyrosine kinase domain (TKD) (128).