Targeted therapies for hematologic malignancies or blood cancers developed in tandem with those for solid tumors: Molecular profiling as a result of sequencing identified targetable signaling pathways. They have evolved considerably from the development and discovery of the tyrosine kinase inhibitor imatinib for chronic myeloid leukemia. Clinical studies are ongoing for novel second- and third-generation agents to overcome resistance to first-generation therapies. The elucidation of mechanisms of resistance is playing an increasingly prominent role in the implementation of targeted therapies in the clinic.