Triple Negative Breast Cancer (TNBC) is defined by a lack of expression of ER, PgR and HER-2. DNA microarray profiling studies have led to the classification of invasive breast carcinoma into five subtypes: luminal A and B, normal breast-like, HER2/neu overexpressing and basal-like subtypes, with clinical implications. Later on, a new subtype, the claudin-low, has been described. Although not synonymous, the majority of TNBCs carry the basal-like breast cancer (BLBC) molecular profile.