HER2 blockade (trastuzumab) in HER2-positive breast cancer, tyrosine kinase inhibitor in CRC and chronic myelogenous leukemia, and inhibitors of EGFR in EGFR-mutated lung cancer are clinically established as examples of targeted therapy [130]. The gene discussed is ERBB2; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.