Objective To further define the molecular mechanism involved in the metastasis process in lung cancer and screen out the genes expressed differentially in the lung cancer.Methods mRNA differential display (DD-PCR) was employed to search the specific genes related to metastasis.The highly expressed fragments were cloned and sequenced.Compared with the data in GenBank,the homologous genes were found.The anchor primers were designed to validate the candidates from DD-PCR by real-time PCR.The structure of the gene was prognosticated by software.Results Nine differentially expressed genes were found.One of the nine genes,which named C3orf1,showed high different expression within the six tested cancer cells.The gene was 858bp long and encoded 285 amino acids.The molecular weight was about 32.2 kD.Analyzed by the bio-software,it was found that the gene was consisted with seven EGF-like domains (EGF_1),three 2Fe-2S ferredoxin/iron-sulfur binding regions (2FE2S_FER_1),two VWFC domains (VWFC_1),two thiolase active sites (thiolase_3),and so on.Conclusions The gene C3orf1 is over-expressed in the lung cancer 95D cells.It may encode a familiar secretary growth factor protein and play important role in stimulating growth of the cells.