Furthermore, with the use of two additional biological markers, cytokeratin 5 (CK5) and epidermal growth factor receptor (EGFR), triple-negative breast cancer (TNBC) tumors can be separated in two distinct subgroups, basal core phenotype (BCP) and non-basal core phenotype (non-BCP) triple-negative tumors. This evidence concerns the gene KRT5 and triple-negative breast carcinoma.