ERBB2 and breast cancer: The 548 samples included 148 luminal A (ER+/PR+, HER2−, Ki-67<20%), 91 luminal B (ER+/PR+, HER2+/Ki-67≥20%), 113 HER2+ (ER-, PR-, HER2+), and 196 basal cell-like (ER−, PR−, HER2−, CK5/6+ and/or EGFR+) breast cancers.