Alterations in levels of different protein kinase C isotypes and their influence on behavior of squamous cell carcinoma of the oral cavity: epsilon PKC, a novel prognostic factor for relapse and survival.

BACKGROUND: Recent results suggest that some PKC isotypes, when overexposed, confer to cultured fibroblasts certain proliferative advantages, and enhanced tumorigenicity in nude mice, suggesting their participation in carcinogenic process. These findings need to be validated through the investigation of potential alterations of these kinases in common forms of human cancers.

MATERIAL AND METHODS: In this prospective study we determined levels of different PKC isozymes by Western blot in tissue extracts from 29 human primary squamous cell carcinomas of the oral cavity, and their respective controls. These expressions were correlated with behavior of tumor and histologic characteristics.

RESULTS: Dramatic alterations in different PKC isotypes were found. Thus, increased levels of isotypes alpha, beta, or gamma, and zeta were found in most of the patients, as well as significant correlations between levels of the isotype epsilon and survival-relapse rate and classical PKC isotypes with irregular morphology of tumoral interphase.

CONCLUSIONS: These results suggest participation of some PKC isotypes (alpha, beta, gamma, and zeta) in the genesis and behavior (epsilon) of oral cancers. Levels of epsilon PKC could be used as prognostic marker.