Figure 1.

Clinical therapeutic strategies for BC. Currently, endocrine therapy, anti-HER2 targeted therapy and chemotherapy constitute the backbone of BC treatment in clinic. Drugs for endocrine therapies include selective estrogen receptor modulators (SERMs), selective estrogen receptor degraders (SERDs) and aromatase inhibitors. SERMs bind ER to antagonize the activity of estrogen, SERDs bind ER to promote its proteasome-mediated degradation, while aromatase inhibitors block the biosynthesis of estrogens from adrenal steroids. Drugs available for anti-HER2-targeted therapy include monoclonal antibodies (trastuzumab, pertuzumab and emtansine) and small molecules (lapatinib and neratinib). Chemotherapy standards for BC treatment are anthracylines and taxanes. In addition, novel therapeutic strategies including targeted therapies beyond HER2 and immunotherapy have been administered in clinical situations (drugs for BC treatment are shown in italic).