Claudin expression is maintained in mucoepidermoid carcinoma of the salivary gland

ABSTRACT Objective The aim of the present study was to investigate the expression of claudin-1, -3, -4, -5 and -7 proteins in mucoepidermoid carcinoma of oral cavity and analyze whether EGF may interfere in the expression of the genes that encode claudins using in vitro models. Material and Methods Using immunohistochemistry, the expression of claudins was searched in 36 histologically graded cases of mucoepidermoid carcinoma. The correlation of expression of claudins with clinical-pathological parameters was evaluated. An in vitro step investigated the influence of EGF on gene expression of claudins by real time RT-PCR technique. Results Claudin-1, -3, -4, -5, and -7 were highly expressed in most mucoepidermoid carcinomas. These expressions were compared with clinicopathological parameters. High expression of claudin-1 was associated with patients over 40 years-old (p = 0.05) and Caucasians (p = 0.024). In vitro experiments demonstrated a tendency for Claudin gene expression increase after EGF stimulus. Conclusions The expression of claudins is maintained in mucoepidermoid carcinoma cells and EGF could be related with this expression. Our results point out to a fundamental biological importance to CLDNs in normal and neoplastic tissue. The expression patterns of CLDNs does not yet allow a clinical application, but the biological knowledge will ground evidence to new studies towards possible target-therapies.