Decreased Expression of Connexin-30 and Aberrant Expression of Connexin-26 in Human Head and Neck Cancer

Abstract

Background: The relation of connexins and carcinogenesis has been studied in various organs and cell lines, with connexins currently being considered tumor suppressors. Materials and Methods: The expression of connexin-26 (Cx26) and connexin-30 (Cx30) in human head and neck carcinomas, as well as in adjacent normal mucosa, was evaluated by immunohistochemistry. Furthermore, the expression of these connexins with regard to apoptosis and cell differentiation was investigated. Results: In the cancer tissues, Cx30 expression was drastically reduced compared to apparently normal mucosa while Cx26 expression was almost the same. The intracellular distribution patterns of Cx26 and Cx30 in cancer cells differed between cancer locations. In the cancer tissues, expression of Cx26 and Cx30 was not related to apoptosis assessed by TdT-mediated dUTP-biotin nick end labeling (TUNEL) reaction or to cell differentiation assessed by immunoreaction to involucrin. Conclusion: The present results suggest that connexins may play a role in the carcinogenesis of head and neck cancer.