Characterization of immunohistochemical markers in triple negative breast carcinomas.

PURPOSE: Triple negative (TN) breast carcinomas (estrogen receptor/ER, progesterone receptor/PR and HER-2/neu negative) constitute 15-25% of all breast carcinomas and have been correlated with aggressive behavior and poor prognosis. Our aim was to describe and characterize the immunophenotype of these tumors in a group of patients from Turkey. METHODS: We used the immunohistochemical markers CK5/6, CK14, EGFR, E-cadherin, p53 and androgen receptor. Formalin-fixed, paraffin-embedded tissues from 51 breast carcinoma patients (36 TN and 15 non TN) were included into this study. RESULTS: The mean values of the distribution of immunohistochemical markers in TN vs non-TN groups were as follows: CK5/6 78.4 vs 5.3%, CK14 84.8 vs 8%, EGFR 87.2 vs 8%, E-cadherin 96.9 vs 53.2%, p53 87.3 vs 7.3% and androgen receptor 89.5 vs 33.3% (all p-values<0.001). CK5/6 stained significantly different in the grade 2 and 3 cases (p=0.035) in the TN group.The other markers demonstrated no significant differences between grades. CONCLUSION: TN breast carcinomas in Turkish patients express basal cytokeratins, and have high levels of p53 compared to non-TN breast carcinomas.