Abstract: Objective To investigate the mechanism of transforming growth factor(TGF)-β1 on metastasis in human ovarian cancer cells.Methods Using RT-PCR, Western Blot and Zymography, we determined the effects of TGF-β1 on the expressions and secretions of MMP-2 and MMP-9 in HO-8910 and HO-8910PM cells.In addition, expressions of TGF-β1, MMP-2 and MMP-9 were determined by immunohistochemistry in normal ovary tissues(31 cases), primary ovarian cancer tissues(45 cases)and metastatic tissues(45 cases).Results We found that the expressions and secretions of MMP-2 and MMP-9 were enhanced by TGF-β1 in HO-8910 cell.There was significant difference regarding the expression of MMP-2 between normal ovarian tissues and primary ovarian cancer tissues(P＜0.05).Significant difference of the expression of TGF-β1, MMP-2 and MMP-9 was also found between primary ovarian cancer tissues and metastatic tissues(P＜0.01).There were correlations between the expression of TGF-β1 and MMP-2(P＜0.05)and between the expression of TGF-β1 and MMP-9(P＜0.05).Conclusions In ovarian cancer, TGF-β1 promotes metastasis by increasing the expression of MMP-2 and MMP-9.