Although targeted therapy for gastric cancer is relatively new, significant progress has been made in this field, for example, the development of HER2 monoclonal antibodies and inhibitors of epidermal growth factor receptors, angiogenesis, multitarget tyrosine kinases, cyclin-dependent kinases, mTOR, c-Met, matrix metalloproteinases, IGF-1R, and HSP 90 [37]. This evidence concerns the gene ERBB2 and gastric cancer.