Triple Negative Breast Cancer: A Tale of Two Decades.

Triple negative breast cancer (TNBC) is a heterogeneous disease entity constituting about 15% of breast cancer cases worldwide. TNBC is associated with poor prognosis and lack of sustained response to conventional chemotherapeutic agents. Tumoral heterogeneity and the presence of several subtypes of TNBC such as Basal like (BL)-1, BL-2, immune-modulatory, luminal androgen receptor, mesenchymal, and mesenchymal/stem like subtype and claudin low subtype, may explain some of the difficulties faced in managing this challenging disease subgroups.