New strategies for triple-negative breast cancer--deciphering the heterogeneity.

Triple-negative breast cancer (TNBC) is a heterogeneous disease; gene expression analyses recently identified six distinct TNBC subtypes, each displaying a unique biology. Exploring novel approaches to treatment of these subtypes is critical because less than 30% of women with metastatic breast cancer survive five years and virtually all women with metastatic TNBC will ultimately die of their disease despite systemic therapy. To date, not a single targeted therapy has been approved for the treatment of TNBC and cytotoxic chemotherapy remains the standard treatment. We discuss the current and upcoming therapeutic strategies being explored in an attempt to "target" TNBC.