FLT3 and chronic myelogenous leukemia, BCR-ABL1 positive: One of the most common genetic alterations is the gatekeeper T315I substitution observed in chronic myeloid leukemia (CML) or Philadelphia chromosome positive (Ph+) acute lymphoblastic leukemia (ALL) and FMS-like tyrosine kinase-3 (FLT3)-activating mutations in acute myeloid leukemia (AML).