ERBB2 and cancer: Notably, the therapeutic efficacy of anti-HER2 drugs in breast[6] and gastric[7] cancers, both characterized by high rates of human epidermal growth factor receptor 2 (HER2) overexpression, has led to a growing interest in the application of anti-HER2 therapy for HER2-overexpressing cholangiocarcinoma, particularly in eCCA and GBC.