Moreover, in the case of metastatic HER2+ breast cancer a tyrosine kinase inhibitor, lapatinib (Geyer et al., 2006), as well an antibody targeting HER2-HER3 dimerization, pertuzumab (Baselga et al., 2012), have also been approved by U.S. Food and Drug Administration (FDA) for treatment in combination with chemotherapy. The gene discussed is ERBB2; the disease is breast cancer.