Abstract: To investigate the protein expression of nuclear factor kappa B (NF-κB) and MMP-9 in NSCLC tissues and the relationship between their expression and metastasis. Methods: Expression of NF-κBp65 and MMP-9 protein in non-small cell lung cancer tissues (n=95,)and normal tissues(n=27) was detected by immunohistochemical staining. Results：(1)The expression rates of NF-κBp65 protein in NSCLC are 44.2%;In the normal tissues are 22.2%.Significant difference were found for NF-κBp65 expression.(2)The expression of NF-κBp65 protein has significant correlation to tissue typing, clinical classification and clinical stage（P<0.05 or P<0.01）, but it has no correlation to age、sex and tumor size (P > 0.05).（3）The expression of MMP-9 protein has significant correlation to tissue typing, clinical classification and clinical stage（P<0.05 or P<0.01）, but it has no correlation to age、sex and tumor size (P > 0.05).(4) There was obviously positive correlation between NF-κBp65 and MMP-9( r=0.217，P<0.05).Conclusion：The results indicate that NF-κBp65 and MMP-9 protein play some role in suppression of the metastasis of non-small cell lung cancer.

Key words: NSCLC, NF-κBp65, MMP-9, tumor metastasis, immunohistochemistry