Subtyping of triple-negative breast cancer: implications for therapy

Triple-negative breast cancer (TNBC) is a heterogeneous disease; gene expression analyses recently identified 6 distinct TNBC subtypes, each of which displays a unique biology. Exploring novel approaches for the treatment of these subtypes is critical, especially because the median survival for women with metastatic TNBC is less than 12 months, and virtually all women with metastatic TNBC ultimately will 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. In this review, the authors discuss recent developments in subtyping TNBC and the current and upcoming therapeutic strategies being explored in an attempt to target TNBC.