Current therapeutic regimens for HER2-positive breast cancer include monoclonal antibodies, tyrosine kinase inhibitors, and cytotoxic chemotherapy, in addition to hormonal therapy for steroid receptor-positive cases, such as trastuzumab, lapatinib, pertuzumab, neratinib and ado-trastuzumab emtansine [5–9]. The gene discussed is ERBB2; the disease is breast cancer.