Differences in the expression profiles of claudin proteins in human nasopharyngeal carcinoma compared with non-neoplastic mucosa.

Several studies have suggested that claudin proteins, which are the main components of tight junction structures, are related to the regulation of cell polarity and cell differentiation. To explore the expression profiles of the tight junction proteins claudin-2, - 5, - 8 and - 9 in nasopharyngeal carcinoma, IHC (immunohistochemical analysis), Western blot and real-time PCR were used to detect the expression profiles of these claudin proteins in nasopharyngeal carcinoma tissues and in non-neoplastic mucosal tissues. According to our study, the expression levels of claudin-2 and claudin-5 were reduced, while the expression of claudin-8 was increased in nasopharyngeal carcinoma tissues in comparison with non-neoplastic mucosal tissues. Correlations between claudin-2 and -5 expression and metastatic progression in nasopharyngeal carcinoma patients were also found. In summary, our research reveals distinct expression profiles of claudin-2, - 5 and - 8 in non-neoplastic mucosal tissues and nasopharyngeal carcinoma tissues. In addition, the expression of these claudin proteins was highly correlated with metastatic progression and prognosis in patients with nasopharyngeal carcinoma and had predictive value for the metastasis and survival of nasopharyngeal carcinoma patients.