Cytokeratin expression is unrelated to hormone receptor expression in breast carcinoma

Introduction: Invasive breast cancer (IBC) is a heterogeneous entity, showing distinct molecular features and biologic behaviour. Immunohistochemistry (IHC) based molecular classification has been recommended for clinical decision making. Variable expression of cytokeratins (CK) is now a major therapeutic determinant in addition to the hormone receptor status, clinical stage and grade of the tumour. Aims and Objectives: This study was conducted to assess the expression of CK 8/18, CK 19, CK5/6 and CK 20 in patients of invasive breast carcinoma and its correlation with hormone receptor status and clinicopathological profile. Materials and Methods: IHC staining for CK 8/18, CK 19, CK5/6 and CK 20 and ER, PR, Her2neu was applied on sections of 43 cases of carcinoma breast using avid in biotin peroxidase technique. The distribution and intensity of staining was recorded and statistical analysis was done using chi square and fischers test. P value of <0> Observations: CK 8/18, CK 19, CK 20 and CK 5/6 was observed in 72%, 83.7%, 13.9% and 18.6% of cases respectively. There was no significant difference of various Cytokeratin expression with ER, PR and Her2neu expression. One fourth of CK5/6 positive cases also expressed ER and PR. CK8/18 correlated positively with CK 19 expression as both are luminal markers. Conclusion: Breast cancer cases could be subdivided into different cellular phenotypes based on the expression of luminal and basal CK. There was no correlation of CK expression with hormone receptor expression. This study has further characterized the heterogeneous nature of breast carcinoma using IHC which may facilitate the physician in making patient diagnosis, prognostication and outcome.