ERBB2 and breast carcinoma: The main molecular subtypes of breast cancer are termed Luminal A (ER+/HER2-), Luminal B (ER+/HER2+/−, higher histological grade, more aggressive than Luminal A), HER2-enriched (ER−/HER2+), and triple-negative (ER−/PR−/HER2-) [1].