AIM: To explore the effects of tumor antigen gene OVA66 on the biological characteristics of tumor cells. METHODS: The eukaryotic expression vector pcDNA3.1-mock and recombined vector pcDNA3.1-OVA66 were transfected into hepatoma cell line SMMC-7721 by LipofectAMINETM 2000. After stable selection and clone proliferation of cells, the expression of OVA66 gene and protein was detected by RT-PCR, Western blot and immunocytochemical (ICC) staining. The cell growth cycle was analyzed by FACS. The ultrastructure was observed under electron microscope. The experiments in cell migration and invasion were performed in vitro. The OVA66-associated genes were analyzed by genechip technique after gene transfection. RESULTS: OVA66 was highly expressed in 7721 cells transfected with pcDNA3.1-OVA66 at mRNA level. Western blot result demonstrated that OVA66 protein content was notably increased compared with that in control cells. Electron microscope and FACS results indicated that OVA66 gene promoted the growth and proliferation of tumor cells. In vitro, the experiments in cell migration and invasion showed that this gene enhanced migration and invasion of tumor cells. The result of genechip demonstrated that the over- expression of OVA66 gene increased the expression of plasminogen activator inhibitor-1 gene (PAI-1), suggesting that it had some effects on tumor invasion and metastasis. CONCLUSION: Tumor antigen gene OVA66 and it's protein demonstrate a series of biological characteristics of tumor cells, which can promote the proliferation, migration and invasion of tumor cells.