Personalized chemotherapy in triple-negative breast cancer: are we ready for prime time?

Triple-negative breast cancer (TNBC) comprises a subgroup of breast tumors characterized by the absence of estrogen- and progesterone-receptor protein expression and human epidermal growth factor receptor-2 (HER2) gene amplification. Approximately 15–20% of all breast tumors are classified as TNBC. Clinically, patients with TNBC have been treated similarly. Because patients with TNBC are not candidates for endocrine or anti-HER2 therapy, chemotherapy remains their most important available systemic therapy and the outcomes are poor compared to other breast cancer subtypes, with median overall survival (OS) reaching fewer than 2 years (1-3).