Clinicopathologic implications of epithelial cell adhesion molecule expression across molecular subtypes of breast carcinoma.

Background: Epithelial cell adhesion molecule (EpCAM), a type I transmembrane protein of the epithelial tissues and known cell adhesion molecule, has been demonstrated to have critical role in carcinogenesis. In breast cancer, EpCAM expression has been associated with poor prognosis. The expression pattern of EpCAM across molecular subtypes of breast carcinoma has been studied in patients reporting to a South Indian multispecialty tertiary care hospital. The prognostic significance of EpCAM expression pattern and probable response to therapy has also been addressed. Materials and Methods: EpCAM expression was assessed by immunohistochemical studies on 200 breast carcinoma tissue samples of different molecular subtypes, including luminal A, luminal B, Her2Neu, and triple-negative breast cancer (TNBC). The expression was scored using the standard scoring system. A correlation was drawn with detailed clinicopathologic annotation and available outcomes data to analyze the influence of EpCAM on prognosis. Results: EpCAM expression varied significantly in the different intrinsic subtypes of breast carcinoma. Differential expression was also established with different grades of breast carcinoma with varying levels of differentiation. We observed strong EpCAM expression in TNBC among other subtypes. Conclusion: The differential expression of EpCAM among intrinsic subtypes of breast cancer and the correlation of EpCAM expression with high-grade breast carcinoma shown in the study have important implications in understanding the role of EpCAM and might form the basis for developing targeted therapies in breast cancer in the future.