RC-48, an ADC consisting of MMAE and the mAb targeting human epidermal growth factor receptor 2 (HER2), is currently under phase II clinical trial to treat urothelial carcinoma, advanced cancer, gastric cancer, HER2-overexpressing gastric carcinoma, advanced breast cancer and solid tumors [8,55]. This evidence concerns the gene ERBB2 and gastric carcinoma.