Claudin 7 is a 22 kDa membrane protein, belonging to the tight junction protein family. Claudin family proteins play an important role in cell polarity, signal transduction and the pathogenesis of a variety of malignant tumors. It has been reported that compared with non neoplastic mucosal tissues, the expression of claudin 7 in laryngeal squamous cell carcinoma is down-regulated, and the expression level is related to distant metastasis, which can be used as a potential predictor of poor prognosis. Therefore, claudin 7 may be a useful immunohistochemical marker for the diagnosis, metastasis and prognosis of laryngeal cancer.