Examples of targeted therapies include amplification of human epidermal growth factor receptor2 (HER2) for HER2 antibody in breast cancer and in gastric cancer and activating EGFR mutations for EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) [5,11,13,38,46,47]. The gene discussed is ERBB2; the disease is gastric cancer.