ERBB2 and cancer: According to the latest data on the 2020 global burden of cancer, the number of new breast cancer cases rapidly reached 2.26 million, and breast cancer becomes the world’s largest cancer.[1] The overexpression of human epidermal growth factor receptor 2 (HER2) (HER2-positive) accounts for 15% to 25% of patients with breast cancer.[2,3] This type is associated with aggressive clinical phenotypes and poor outcomes.[4] The application of targeted drugs significantly improved the survival rate of HER2-positive breast cancer.