Abstract: Objective To determine the expression and clinical significance of HIF-1α，VEGF and TGF-β₁ in non-small cell lung cancer（NSCLC）. Method The immunohistochemical SP method was used to analyze expression of HIF-1α，VEGF and TGF-β₁ in 85 samples of NSCLC tissue and 13 samples of normal lung tissue. Results A greater proportion of NSCLC tissue than normal lung tissue was positive for HIF-1α，VEGF and TGF-β₁.Expression of these proteins positively correlated with NSCLC clinical stage and lymph node metastasis（P<0.01）.However，no correlation was observed between expression of HIF-1α，VEGF and TGF-β₁ and other clinico-pathological features such as age，sex，pathology type or degree of differentiation（P>0.05）.Levels of HIF-1α，VEGF and TGF-β₁ correlated positively with one another in NSCLC tissue（P<0.05）. Conclusion Elevated expression of HIF-1α，VEGF and TGF-β₁ may be associated with tumor invasion and metastasis in NSCLC.

Key words: Lung neoplasms, HIF-1α, VEGF, TGF-β₁