Targeted therapies have transformed the way cancer is understood and treated, and allow personalization of treatment according to each individual’s tumor characteristics. Targeted cancer therapies are drugs or other substances that block the growth of cancer by interfering with specific molecules (molecular targets or receptors) that are involved in the growth, progression and spread of cancer. In the case of hormone therapies, the interaction is with estrogen receptors; in the case of human epidural growth factor 2 (HER2) targeted therapy (e.g., trastuzumab), interaction is with the HER2 receptor. Accurate testing for the presence of the estrogen receptor (ER) +/- the progesterone receptor (PR) is required for the effective use of hormonal therapy (tamoxifen, aromatase inhibitors and others) and accurate testing of HER2 receptor status is required prior to consideration of HER2 targeted therapy. While the percentage may vary by population, about two out of three breast cancers are hormone receptor positive, and one in five breast cancers are HER2 receptor positive. Hormone therapy and targeted therapies can be given as neoadjuvant (preoperative) therapy, adjuvant (postoperative) therapy and as treatment for patients with metastatic disease. Hormonal therapy can also be used as preventive therapy in select high-risk women.