ERBB2 and breast cancer: Galen Consensus 2011, the molecular subtypes of BC are identified as luminal A (ER+/PR+/HER2-/low Ki-67), luminal B (ER+/PR+/HER2-/+/high Ki-67), HER2-overexpression (ER-/PR-/HER2+) and triple-negative/TNBC (ER-/PR-/HER2-).