ERBB2 and breast ductal adenocarcinoma: Clinically, the ductal carcinoma is evaluated according to the expression profile of the estrogen receptor (ER), progesterone receptor (PR) and epidermal growth factor type 2 receptor (HER2) and sub-classified into: hormone-positive receptors (luminal A, Luminal B), HER2-positive and triple negative for hormonal receptors (basal-like) [4].