ERBB2 and breast cancer: Overall, 61.0% of the cohort had ER/PR+/HER2- (luminal A) breast cancer, 16.5% the ER/PR/HER2+ subtype (luminal B), 6.7% the ER/PR-/HER2+ (Her2-enriched) subtype and 15.8% the ER/PR-/HER2- (triple negative) subtype.