ERBB2 and breast carcinoma: A significant body of evidence gathered over the course of more than 10 years has repeatedly demonstrated the prognostic significance and predictive ability of the four intrinsic subtypes of breast cancer (Luminal A, Luminal B, HER2-enriched, and Basal-like) [1–8], which were first described in 2000 by Perou et al. [9].