These approaches are exemplified by the use of BCR-Abl inhibitors for the treatment of Chronic Myelogenous Leukemia (CML), HER2-directed monoclonal antibodies and tyrosine kinase inhibitors for the treatment of HER2+ breast tumors, and PARP inhibitors for the treatment of BRCA1/2-mutant ovarian cancers. The gene discussed is ERBB2; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.