Expression patterns of claudins 1, 4, and 7 and their prognostic significance in nasopharyngeal carcinoma.

PURPOSE: Tight junction (TJ) proteins in the cells organize paracellular permeability, and they have a critical role in apical cell-to-cell adhesion and epithelial polarity. In our study, the expression patterns of claudins 1, 4, and 7 and their relationship with prognosis were determined in patients with nasopharyngeal carcinoma. METHODS: Claudins 1, 4, and 7 were stained immunohistochemically in 18 biopsy samples of nasopharyngeal carcinomas that included non-neoplastic surface epithelium and dysplastic epithelium in addition to the tumor tissue. The files of these patients were scanned and the stage of disease and treatment received were obtained along with demographic data such as age and gender. RESULTS: Overexpression of claudins 1, 4, and 7 in non-neoplastic surface epithelium was found in 14 (77.7%), 16 (88.8%), and 10 (55.5%) cases respectively; in dysplastic surface epithelium overexpression was found in 8 (44.4%), 13 (72.2%), and 4 (22.2%) cases, respectively; and in invasive tumor areas overexpression was found in 13 (72.2%), 9 (50%), and 10 (55.6%) cases respectively. Increased claudin 4 expression was related to advanced stage (p=0.014). There was a significant relationship determined between claudin 4 and 7 expression and decreased survival (p=0.018, p=0.024, respectively). CONCLUSION: The fact that a statistically significant relationship was found between claudin 4 expression and advanced stage, and similarly a statistically significant relationship was found between claudin 4 & 7 expression and decreased survival gives rise to thoughts that especially claudin 4 and 7 could have different tumorigenic effects on nasopharyngeal carcinoma besides their known adhesion characteristics.