ERBB2 and breast cancer: Profiling of gene expression has identified the four main intrinsic molecular subtypes of BC, including luminal A, luminal B, human epidermal growth factor receptor 2-enriched (HER-2), and triple negative (TN), each of which exhibits distinct molecular receptor statuses and therefore requires tailored therapeutic approach, such as endocrine therapy or neoadjuvant systemic therapy (NST) (3–5).