Update on Precision Medicine in Breast Cancer.

Precision medicine approaches have found applications in the treatment of several tumor types and have led to rapid advancement in the number of available therapies for some difficult-to-treat diseases. In comparison to tumors like EGFR-mutated lung cancer, and BRAF-mutated melanoma for example, precision medicine in breast cancer is still in its infancy despite the much earlier identification of targets like ER and HER2. Though significant progress has been made in new therapies for hormone-receptor-positive and HER2-positive breast cancers, identification of molecular heterogeneity and lack of other valid reproducible targets in triple-negative breast cancer remain a challenge. In this chapter, we outline the recent advances in technology and targeted treatments for breast cancer, the remaining challenges and ongoing efforts to address these to make precision medicine a reality for all breast cancer patients.