Mutations within the juxtamembrane domain (most commonly internal tandem duplications [ITD] and/or the tyrosine kinase domain [TKD]) of fms-related receptor tyrosine kinase 3 (FLT3) are identified in approximately 30% (ITD: ~20%, TKD: ~7%) of patients with newly diagnosed AML [13,14,15]. This evidence concerns the gene FLT3 and acute myeloid leukemia.