There are mainly five categories of molecular targeted drugs applicable for GC, which are targeting human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), Claudin 18.2 (CLDN 18.2) and mammalian target of rapamycin (mTOR) (25). The gene discussed is ERBB2; the disease is gastric cancer.