Expression and clinical significance of PAK4 in non-small cell lung cancer

AIM: To investigate the expression and clinical significance of PAK4 in the cell lines and tissues of non-small cell lung cancer (NSCLC). METHODS: PAK4 expression in human bronchial epithelial (HBE) cells, NSCLC cell lines, NSCLC tissues and adjacent non-tumor tissues were assessed by immunohistochemistry, real-time PCR and Western blot. Prognostic value of PAK4 expression was evaluated by Kaplan-Meier analysis and Cox regression. RESULTS: PAK4 was over-expressed in the NSCLC cell lines at both mRNA and protein levels compared with HBE cells (P<0.05). PAK4 was over-expressed in the NSCLC tissues at both mRNA and protein levels compared with adjacent non-tumor tissues (P<0.05). PAK4 was over-expressed in the metastatic NSCLC tissues compared with the primary NSCLC tissues (P<0.05). Higher PAK4 staining scores were positively correlated with differentiation, lymph node metastasis, distant metastasis, and clinical stage. Kaplan-Meier analysis and log-rank test showed that overall survival was significantly different between the patients with up-regulated PAK4 and the patients with down-regulated PAK4(P<0.05). PAK4 over-expression was associated with NSCLC progression.CONCLUSION: Increased PAK4 expression was associated with tumor invasion, metastasis and prognosis in the patients with NSCLC. PAK4 is an important prognostic marker and potential therapeutic target in NSCLC.