Targeted therapy in breast cancer is used in the management of HER2 positive cases and it involves monoclonal antibodies against the HER2 receptor (trastuzumab, pertuzumab, and trastuzumab-emtansine, in which the humanized HER2 antibody is conjugated to DM1, a tubulin toxin) and the tyrosine kinase inhibitor lapatinib [11]. The gene discussed is ERBB2; the disease is breast carcinoma.