Subsequently, EGFR inhibitors (EGFRi) such as cetuximab, erlotinib and gefitinib were developed to treat EGFR-mutant NSCLC (Kazandjian et al., 2016); BRAF/MEK inhibitors (BRAFi/MEKi) were developed for BRAF-mutant melanoma; and epidermal growth factor receptor 2 inhibitors (HER2i) were developed for the treatment of HER2 positive (HER2+) breast cancer (Harbeck and Gnant, 2017). The gene discussed is EGFR; the disease is breast cancer.