Objective To clarify the relationship between CT120,a novel human plasma membrane-associated gene,and the proliferation of lung adenocarcinoma cell line A549.Methods Expression vector(pcDNA3.1)containing antisense oligonucleotides of CT120 was constructed and transfected into the adenocarcinoma cell line A549.RT-PCR and Western blot detected the expression of CT120.Meantime,flow cytometry and soft agarose colony formation were applied for cell proliferation,and P53,CyclinD1 and CDK4 were detected by RT-PCR.ResultspcDNA3.1 containing antisense oligonucleotides of CT120 was successfully constructed and inhibited the expression of CT120 effectively by RT-PCR and Western blot.The expression of P53 was up-regulated and the expression of CyclinD1 and CDK4 were down-regulated.Conclusion The down-regulation of CT120 expression by antisense oligonucleotides technique may be a potential drug target for treatment of lung cancer.