FLT3 and acute myeloid leukemia: These differences in signaling may help to explain distinct disease courses and progression patterns and thus a different prognosis: while FLT3–ITD mutations are associated with an aggressive disease course and are strong predictors of rapid relapse and short overall survival (OS) after chemotherapy, AML patients with FLT3–TKD mutations develop a less-aggressive disease with a somehow better prognosis.