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

Claudins are major tight junction proteins that regulate the integrity and function of tight junctions. Aberrant expression of claudins has been shown in various carcinomas with diverse prognostic implications. However, their expression pattern and prognostic value have not been investigated in nasopharyngeal carcinoma. This is the first study to characterize the expression pattern of claudins 1, 4, and 7 in a cohort of 176 patients with nasopharyngeal carcinoma and a minimum follow-up of 9.4 years. Immunohistochemistry with semiquantitative assessment of expression of claudins 1, 4, and 7 was performed on 176 biopsy specimens. Results were correlated with sex, age, extent of tumor, lymph node status, the presence or absence of distant metastasis, and patient survival. High expression of claudins 1 and 4 (72.2% and 88.1%) and low expression of claudin 7 (82.4%) were frequently detected. Low claudin 4 expression (P = .020) and high claudin 7 expression (P < .001) were associated with distant metastasis. Elevated claudin 7 expression also correlated with high tumor stage (P = .001). Furthermore, decreased claudin 4 expression (P = .003) and increased claudin 7 expression (P < .001) independently predicted shorter distant metastasis-free survival by Cox regression analysis. Claudin 4 and claudin 7 may be a novel biomarker for the prediction of distant metastasis and unfavorable prognosis in nasopharyngeal carcinoma.