The Expression of Basal Cytokeratins in Breast Cancers

Abstract

Introduction: Treatment for breast cancer is based on the expression of the immunomarkers such as ER, PR and HER2/neu. Cases which are negative to all the three immunomarkers, are called Triple Negative Breast Cancers (TNBC) and they have a poor prognosis. Recent studies have shown that some of the TNBCs express cytokeratins CK 5/6 (subcategorizing them as basal-like breast cancers) and these respond well to anthracycline-based chemotherapy. Aim and Objectives: To study the expression of basal cytokeratins CK 5/6 in breast carcinomas reported in our centre and to correlate with histological type, grade, size, clinical features and ER, PR and HER2/neu status. Methods: Tissues of 44 cases of breast carcinoma diagnosed between June 2009 and May 2014 were retrieved. Immunohistochemical staining for CK 5/6 was done and it was correlated with parameters such as histopathological type, grade, size, invasion and ER, PR and HER2/neu status. Results: Eight of the breast carcinomas (18%) were categorized as Triple Negative Breast Cancers (TNBC) as they were negative for ER, PR and HER2/neu. Four of the TNBCs (50%), were positive for CK 5/6. Significant statistical correlation was observed between the size of the tumour and positive CK 5/6 expression. All CK 5/6 positive cases were of high grade. Conclusion: The routine use of CK 5/6 is recommended in all cases of TNBCs, as 50% of them are positive for these markers. Patients in this subcategory could benefit from anthracycline-based chemotherapy.