ERBB2 and breast cancer: Most breast cancer (BC) cases originate in the connective tissue ducts (ductal carcinoma in situ, DCIS) or lobules (lobular carcinoma in situ, LCIS) and can be classified into four main subtypes: hormonal (luminal A or B), human epidermal growth factor receptor (HER2-positive), and triple-negative breast cancer (TNBC); each one with different standard treatments [4,5,6,7,8].