We discuss major molecular targets and personalized strategies across hematologic malignancies: FLT3 and IDH1/2 in acute myeloid leukemia (AML); Philadelphia chromosome–positive and Ph-like subtypes in acute lymphoblastic leukemia (ALL); BCR-ABL1 in chronic myeloid leukemia (CML); TP53 and IGHV mutations in chronic lymphocytic leukemia (CLL); molecular subtypes and immune targets in diffuse large B-cell lymphoma (DLBCL) and other lymphomas; and B-cell maturation antigen (BCMA) in multiple myeloma. The gene discussed is IDH1; the disease is lymphoma.