The paradox of triple negative breast cancer: novel approaches to treatment.

Breast cancer that lacks expression of estrogen/progesterone receptors and overexpression of the human epidermal growth factor receptor2 (HER2), i.e. triple-negative breast cancer (TNBC), is not amenable to current targeted therapies and carries a poor prognosis. This review discusses the natural history of TNBC and published literature in the relevant treatment landscape, with a focus on newer therapies. Compared with other subtypes of breast cancer, TN tumors have higher response rates to neoadjuvant chemotherapy; however, this advantage is not clearly translated into the metastatic setting and has not improved these patients' overall survival. Numerous cytotoxic and targeted strategies have demonstrated efficacy or are under investigation. Strategies showing promise in this difficult-to-treat group of patients include cytotoxic therapy with platinum-containing agents, ixabepilone, and novel targeted approaches such as poly(ADP-ribose) polymerase inhibitors.