Clinical significance of high expression of proliferating cell nuclear antigen in non-small cell lung cancer

Although proliferating cell nuclear antigen (PCNA) plays an important role in tumor proliferation and its expression level is closely related to the biological activity of tumor cells, PCNA expression in non-small cell lung cancer (NSCLC) has been seldom reported. In this study, we aimed to investigate the significance of PCNA expression in NSCLC tissues. PCNA expression in NSCLC and adjacent tissues were assessed by immunohistochemistry (IHC), western blotting, and reverse transcription polymerase chain reaction. Single factor analysis was used to study the relationship between the expression of PCNA and clinicopathological features of NSCLC. Multi-factor Cox survival analysis was used to evaluate the relationship between the expression of PCNA and overall survival of postoperative NSCLC patients. The areas under the receiver operating characteristics were calculated to evaluate the value of PCNA expression level in predicting the 3-year survival of NSCLC patients. IHC analysis showed that the positive expression rates of PCNA protein in NSCLC and adjacent tissues were 91.79% (257/280) and 25.83% (31/120), respectively. Western blotting confirmed that PCNA protein level was significantly higher in NSCLC tissues than in the adjacent tissues (P