ERBB2 and breast cancer: The distribution of breast cancer subtypes was as follows: HR+/HER2− (N = 453, 42.7%), HR−/HER2− (triple negative) (N = 258, 24.3%), HR−/HER2+ (HER2-enriched) (N = 180, 17.0%), HR+/HER2+ (N = 170, 16.0%).