ERBB2 and breast carcinoma: Currently, breast cancer can also be classified into six molecular intrinsic subtypes: luminal A, luminal B, HER+, normal-like, basal (also known as triple-negative), and claudin-low, each based on their unique phenotype, tumor grade, and molecular characterizations including hormone receptors and human EGF-like receptor 2 (HER2) receptor status [37].