CYTOKERATIN-18 EXPRESSION IN SQUAMOUS-CELL CARCINOMA OF THE HEAD AND NECK

Cytokeratin (CK) expression was studied in squamous cell carcinomas of different subsites in the head and neck by using cryostat sections fr om 27 head and neck squamous cell carcinomas (HNSCCs)and 6 cell lines established from HNSCC. All tissues were analyzed immunohistochemicall y with a panel of monospecific anti-keratin monoclonal antibodies. Mos t carcinomas recapitulated the expression pattern of keratins present in the basal layer of normal epithelium from the site of tumor origin. Regional differences in the expression of simple-epithelial type of k eratins in stratified (pseudostratified) epithelia were to a large ext ent repeated in corresponding carcinomas. In the present study, locali zation of various keratins were surveyed and CK 18 specific monoclonal antibodies were specifically used to distinguish SCCs of the larynx o r hypopharynx from CCs of the oral cavity. CK 18 staining of almost al l tumor cells was detected in 11 of 12 SCCs of the larynx and hypophar ynx, but was only detected sporadically in 3 of 9 SCCs of the oral cav ity. The present results show that CK 18 typing might be useful for di stinguishing sites of origin of various HNSCCs. Findings also indicate that CK 18 expression in SCC might be modulated by microenvironmental factors.