ERBB2 and gastric cancer: Despite the known overexpression of HER2 in various tumors, there are still conflicting data regarding its role as a carcinogenic driver or prognostic marker for urothelial carcinoma (Krüger et al., 2002; Bellmunt et al., 2015), Notably, treatment with ADC targeted HER2 has significantly improved survival rates for patients with HER2+ breast cancer and gastric cancer.