Molecular heterogeneity of triple-negative breast cancer

Triple-negative breast cancers (TNBCs) are a group of aggressive breast cancers with a greater incidence of relapse, stage-for-stage, than ER/PR-positive and HER2-positive breast cancers, despite optimum loco-regional and systemic therapy. To date, no single targeted therapy has been approved for treatment of TNBC, and cytotoxic chemotherapy remains the standard systemic treatment. Recently, gene expression analysis identified six distinct TNBC subtypes, each with unique biology. In this review we discuss current and forthcoming therapeutic strategies and novel approaches to targeted treatment of these TNBC subtypes. © 2014 Springer Science+Business Media.