Comparative proteomic analysis, combined with 2-DE separation and MALDI-TOF identification, was utilized to compare the protein expression profiles between highly and lowly metastatic subpopulations(i.e.PLA801D and PLA801C) and 11 metastasis-associated proteins were identified and further validated by 1-D Western blotting, Northern blot and/or semi-quantitative RT-PCR analysis. Compared with that in lowly metastatic subpopulation, CK18, TGLC, GDIR, TPMF, IL-18 and ANX1 were significantly up-regulated, while ER60, CH60, PDX1, CLI1 and KCRB were significantly down-regulated in highly metatsatic subpopulation. Most of the candidate proteins have been evidenced to be somehow associated with various aspects of tumor metastasis such as cell growth, motility, invasion, adhesion, apoptosis and tumor immunity, etc. Up to now, CLI1 and IL-18 have not been reported to be associated with lung metastasis, which implied that CLI1 and IL-18 might be new metastasis-associated proteins of lung cancer.