N(%): Number of patients (percentage); HER2: Human epithelial receptor 2; ICH: Immunohistochemistry; ISH: In situ hybridization; NST: Invasive ductal carcinoma of no special type; T-DM1: Trastuzumab emtansine; T-DXd: Trastuzumab deruxtecan. Here, ERBB2 is linked to breast ductal adenocarcinoma.