Immunohistochemical evaluation of expression of cytokeratin 19 in different histological grades of leukoplakia and oral squamous cell carcinoma.

Recent progress in understanding the biology of keratins together with the development of monoclonal antibodies to individual keratin proteins provide the foundation for studying the keratin expression in normal and pathological oral epithelia. Cytokeratin (CK) alterations have been reported in carcinomas and these have been associated with specific aspects of tumour behaviour. Immunohisto-chemistry with monospecific CK19 antibody was used to study the expression pattern in normal mucosa, dysplasias, and oral squamous cell carcinomas (OSCC). In non-keratinzed normal mucosa, CK19 was detected in the basal cell layer, while in dysplasias (diagnosed in H and E stained sections, mild-severe) stained strongly for CK 19 in the basal and supra basal cell layers indicating layer specificity for CK 19 expression. In OSCC, in the number of CK19 labelled cells increased from well to poorly differentiated tumour. Thus the results of the present study indicate an alteration in synthesis of keratin proteins when exposed to carcinogens.