Treatment of triple negative breast cancer (TNBC): current options and future perspectives.

Breast cancer is not considered anymore a unique disease. Microarray gene expression analysis led to the identification of 4 major breast cancer "intrinsic" subtypes, including hormone receptor (HR)-positive luminal A and B, human epidermal growth receptor 2 (HER2)-positive and basal-like breast cancer (BLBC). These subtypes have distinct phenotypes, molecular profiles, clinical behaviour and response to therapy, with the BLBC carrying the worst outcome. Microarray analysis is not feasible in routine practice and therefore oncologists rely on a simpler immunohistochemical (IHC) classification to identify relevant breast cancer subtypes. Triple negative breast cancer (TNBC) is defined by the absence of oestrogen receptor, progesterone receptor and HER2 expression at IHC analysis. TNBC is strictly related to BLBC and, given the lack of common therapeutic targets, represent a major challenge for breast oncologist. In this review we will summarize the updated knowledge on TNBC, with emphasis on its current treatment and on the new therapeutic options under development.