BACKGROUND & OBJECTIVE: Matrix metalloproteinases (MMPs)play an important role in cancer cell invasion,and metastasis by degrading the extracellular matrix (ECM). The activities of MMPs are regulated by tissue inhibitor of metalloproteinases (TIMPs). This study was to detect mRNA expression of MMP-9, 2, 7, and TIMP-1, 2, 3 in ovarian tumor tissues,and explore their correlations with clinicopathologic characteristics,and prognosis of patients with ovarian cancer. METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR)was used to assay the positive rates,and half-quantity values of MMP-9, 2, 7, and TIMP-1, 2, 3 mRNA in 48 cases of malignant ovarian tumor tissues, 21 cases of benign ovarian tumor tissues, and 22 cases of normal ovarian tissues. RESULTS: The positive rate of MMP-9 mRNA, and the half-quantity values of MMP-9,MMP-2 were significantly higher in malignant tumor tissues than those in normal ovarian tissues (P< 0.05). The positive rates and half-quantity values of TIMP-2,MMP-7,TIMP-3 mRNA were significantly higher in malignant and benign ovarian tumor tissues than those in normal ovarian tissues (P< 0.05). The ratio of MMP-9/TIMP-1 was higher in malignant ovarian tumor tissues(0.91+/-0.67) than that in normal ovarian tissues (0.14+/-0.33)(P< 0.05). The expression level of MMP-9 mRNA was higher in ovarian cancer tissues of stage III-IV(1.13+/-0.66) than those of stage I-II(0.60+/-0.54)(P< 0.05). The mean survival time of MMP-9 positive patients was (43.00+/-17.12) months,and cumulate survival rate was 47.37%,significantly lower than that of MMP-9 negative patients (100%). CONCLUSIONS: MMP-9, MMP-2, MMP-7, TIMP-2, TIMP-3 are over-expressed in ovarian malignant tissues. The over-expression of MMP-9, and the imbalance between MMP-9 and TIMP-1 play important roles in the progress of advanced ovarian cancer. MMP-9 may be a useful prognostic marker for patients with advanced ovarian cancer.