FLT3 and acute myeloid leukemia: Acute myeloid leukemia (AML) is a heterogeneous disease and mutations in the gene encoding fms-related tyrosine kinase 3 (FLT3; CD135) is one of the most common negative prognostic markers in AML, present in 20 % of all pediatric AML patients and 30 % of all adult AML patients [1–4].