Abstract: Objective To detect serum levels of IL-17 and VEGF in patients with non-small cell lung cancer（NSCLC） and assess their clinical significance. Methods Serum levels of IL-17 and VEGF were determined in 52 NSCLC patients and 26 healthy controls using avidin-biotin complex ELISA.The levels as well as clinicopathological features were compared between the two groups. Results Serum levels of both IL-17 and VEGF levels were significantly higher in patients than in controls（P=0.000）.In NSCLC patients， serum IL-17 negatively correlated with VEGF expression （r=-0.88，P=0.000）.IL-17 expression was higher in smokers than non-smokers（P=0.048） and higher in squamous cell carcinoma patients than in adenocarcinoma patients（P=0.001）.IL-17 concentration decreased and VEGF concentration increased with increasing NSCLC grade.Serum VEGF level was significantly higher in patients with poorly differentiated tumors than in those with well-differentiated ones（P=0.000）. Conclusions Serum levels of IL-17 and VEGF were significantly elevated in NSCLC patients and were strongly associated with clinicopathological features. Therefore，assaying IL-17 and VEGF may be useful for evaluating the prognosis of NSCLC patients.

Key words:  Lung neoplasms, Non-small cell lung cancer, IL-17, VEGF, Avidin-biotin complex enzyme-linked immunosorbent assay