[Changes of simple epithelial cytokeratin during oral carcinogenesis]

To investigate whether the simple epithelial cytokeratin CK18 and CK19 can be used as a marker of oral precancerous lesions.

Formalin-fixed, paraffin-embedded tissue sections of normal oral mucosa, epithelial hyperplasia, mild epithelial dysplasia, moderate epithelial dysplasia, severe epithelial dysplasia and oral squamous cell carcinomas were stained with a CK18-specific antibody and CK19-specific antibody respectively by LSAB immunohistochemical method. The stained sections were observed under light microscopy. The results were described and analyzed with Rank Sum Test.

CK18 was not detected in normal and abnormal oral tissue sections. But in normal nonkeratinized mucosa, CK19 was detected in the basal cell layer dispersively. In epithelial dysplasia, CK19 was detected in the suprabasal cell layer and the number of CK19-positive cell layers was correlated with the dysplasia degree of epithelia. Furthermore, CK19 was detected in oral squamous cell carcinoma, especially in the poor-differentiated cancer cells.

CK19 expression in suprabasal cell layer of oral mucosa can be used as a candidate marker for diagnosis of oral precancerous lesions and determination of the differentiation level of oral squamous cell carcinoma.