Immunohistochemical Differentiation of Triple Negative Breast Cancer.

Based on immunohistochemical staining for the basal markers cytokeratin 5/6 (CK 5/6), cytokeratin 14 (CK 14) and P-cadherin, triple negative tumors (TNT) are divided into two groups: 1) basal-like (BL) positive for one or all three markers; and 2) non basal-like (NBL) negative for all three markers. Even though the different origin of the cells of these two types of tumors implies different biological properties, they had been treated as one entity until recently. This paper analyzes TNT collected from 150 patients and distributed into two groups according to the results of immunohistochemical analysis, i.e. BL 116 (77.3%) and NBL 34 (22.67%). In this study, CK 5/6, CK 14 and P-cadherin were used as markers for identifying BL tumors. The immunohistochemical reaction was positive for CK 5/6 in 37%, for CK 14 in 50.86% and for P-cadherin in 68.34% of cases. The subclassification of triple negative breast cancer using the basal markers CK 5/6, CK 14 and P-cadherin has enabled identification of BL and NBL breast cancers in a proportion that is in line with the only accurate analysis of TNT gene expression. Using the mentioned combination of markers in daily practice is easy to perform and economically affordable.