FLT3 and acute myeloid leukemia: Internal tandem duplication of the Feline McDonough Sarcoma (FMS)‐like tyrosine kinase 3 (FLT3‐ITD) is one of the most clinically relevant mutations in acute myeloid leukemia (AML), with a high FLT3‐ITD allelic ratio (AR) (≥0.5) being strongly associated with poor prognosis.