CLDN4 and nasopharyngeal carcinoma: Hsueh C have reported the expression of claudin- 1, − 4 and − 7 in nasopharyngeal carcinoma patients, and revealed that claudin-4 and claudin-7 may be a novel biomarker for the prediction of distant metastasis and unfavorable prognosis in nasopharyngeal carcinoma [33].