S-phase kinase-associated protein 2 (Skp2) is one of the positive regulators of the cell cycle that promote Ubiquitin-mediated proteolysis of the cyclin-dependent kinase inhibitor p27. Its overexpression has been implicated in tumorigenesis. In this study, we investigated the expression of Skp2 in human nonsmall cell lung cancer (NSCLC) and its relationship with expression of p27 protein. The expression of Skp2 and p27 protein were detected in 68 NSCLC, 17 normal bronchial epithelium by the

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... ue chip and immunohistochemistry technology. Skp2 was only expressed in NSCLC patients, there was closely relationship among Skp2 expression and histological subtype, cellular differentiation, sex and smoking; Otherwise, there was no relationship among skp2 expression and age or TNM stage. The expression of p27 protein was found in normal bronchial epithelial cells, and the expression was reduced in NSCLC. The expression of p27 was significantly reduced in patients with positive expression of Skp2. Expression of Skp2 was negatively correlated with expression of p27. The expression of Skp2 is up-regulated in NSCLC, and overexpression of Skp2 reduces the protein level of p27 through ubiquitin-dependent degradation, indicating Skp2 may play an important role in oncogenesis and development of NSCLC.