Expression of the Epithelial Cell Adhesion Molecule and Cytokeratin 8 in Head and Neck Squamous Cell Cancer: A Comparative Study.

The epithelial cell adhesion molecule (EpCAM) is a well-known and widely accepted tumor-associated antigen in head and neck squamous cell carcinoma (HNSCC). In contrast, little is known about cytokeratin 8 (CK8), an intermediary filament protein, recently associated with HNSCC. Studies demonstrated an aberrant expression on the cell surface of different carcinomas of both antigens. We performed an immunohistochemical study on the expression pattern of CK8 in comparison to EpCAM on cryosections, followed by microscopic quantitative and semi-qualitative analyses. Both antigens showed heterogenous expression both in individual carcinomas and between different carcinoma types. Furthermore, the expression of CK8 is clearly dependent on the degree of histological tumor cell differentiation. With increasing de-differentiation, the amount of CK8 expression increased, which was not seen for EpCAM. The expression of EpCAM was high on all carcinomas independent of their anatomical localization. Regarding CK8, there seems to be a correlation between the expression grade and the anatomical site. The application of CK8 may provide additional supplementary information on HNSCC.