ERBB2 and neoplasm: In fact, this heterogeneous neoplasm has been classified into 5 subtypes based on gene expression profile: (1) luminal A-like, (2) luminal B-like HER2−, (3) luminal B-like HER2+, (4) HER2-enriched, and (5) basal-like triple-negative (TN); all of these have major differences in incidence, biomarkers, treatment strategies, aggressiveness and prognosis [2].