Syntenin overexpression in human lung cancer tissue and serum is associated with poor prognosis

BACKGROUND: Lung cancer is the major malignant tumour. The present study was conducted to determine the expression level of syntenin in lung cancer tissues and serum from lung cancer patients and to explore its clinical significance. METHODS: Syntenin expression levels were determined in paraffin-embedded lung cancer tissue specimens (n = 191) using immunohistochemistry. The mRNA expressions of syntenin in fresh lung cancer tissues and the paracancerous tissues were examined by RT-qPCR (n = 25). Syntenin and VEGF expression levels were measured in serum from patients with lung cancer (n = 60) and control subjects (n = 30) using ELISA. The associations between syntenin and the clinicopathological features or prognosis in 191 patients with lung cancer were analysed. The correlation between the syntenin and VEGF levels in serum from 60 lung cancer patients was analysed. RESULTS: The expression levels of syntenin were significantly higher in lung cancer tissues than in paracancerous tissues based on immunohistochemistry and RT-qPCR, and elevated syntenin expression was significantly associated with tumour size (P = 0.002), TNM stage (P = 0.020), tumour distant metastasis (P = 0.033), overall survival (OS) (P = 0.002) and progression-free survival (PFS) (P = 0.001). Multivariate analysis revealed that increased expression of syntenin was an independent risk factor for OS (P = 0.006) and PFS (P < 0.001) in lung cancer patients. The expression levels of syntenin and VEGF in serum from lung cancer patients were higher than those from control subjects (P < 0.001, P < 0.001, respectively), and their expression levels were positively correlated (r = 0.49, P < 0.001). CONCLUSIONS: Syntenin expression is upregulated in lung cancer patients, and its serum expression level is positively correlated with VEGF. Moreover, syntenin overexpression was correlated with poor prognosis in patients with lung cancer.