Abstract: Objective: The F-box protein Skp2 is required for the ubiquitin-mediated proteolysis of the cyclin-dependent kinase inhibitor P27kip1. Overexpression of Skp2 has been reported in many cancers including breast carcinoma, gastric carcinoma and prostate cancer. The purpose of this study is to investigate the correlation of Skp2 and P27kip1 expression with the clinical pathological features of nasopharyngeal carcinoma, and the correlation between expression of Skp2 and P27kip1 in nasopharyngeal carcinoma.　Methods: Thirty-nine cases of nasopharyngeal carcinoma and twenty-four cases of chronic nasopharyngitis were enrolled in this experiment. All specimens were proved by formallin-fixed paraffin-embedded slides with the hematoxylin eosin staining. Expression of Skp2 and P27kip1 was determined by using an immunohistochemical staining (PV-9000 two-step kit). Result: The Skp2 labeling frequency (71.79%) in nasopharyngeal carcinoma was significantly higher than that (41.67%) in chronic nasopharyngitis(P＜0.05). The positive rate of P27kip1 expression in nasopharyngeal carcinoma was 35.90%, which was remarkably lower than that (79.17%) in chronic nasopharyngitis (P＜0.01). Expression of Skp2 and P27kip1 protein in nasopharyngeal carcinoma was correlated with the clinical stage and cranial nerve encroachment (P＜0.05), but not correlated with the patient age, sex, histological grade, or lymph node metastases (P＞0.05). Skp2 expression was inversely correlated with P27kip1 in nasopharyngeal carcinoma（rs=-0.373, P=0.019）. Conclusion: Expression of Skp2 protein may decrease the P27kip1 level in human nasopharyngeal carcinoma, indicating it is involved in the development of human nasopharyngeal carcinoma. Skp2 and P27kip1 may be used as hopeful markers for predicting the clinical pathological features and the prognosis of these patients.

Key words: Nasopharyngeal carcinoma, Skp2, protein, P27kip1, protein, Cell cycle