Activating mutations of the FLT3 gene most commonly occur as either internal tandem duplications (FLT3-ITD) in about 25% of AML cases or as point mutations in the intracellular tyrosine-kinase domain (FLT3-TKD) in up to 10% of all AML cases (Figure 2) [16,17]. The gene discussed is FLT3; the disease is acute myeloid leukemia.