[Expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in the hepatocellular carcinomas]

Abstract

Objective: To explore the expression and clinical prognostic significance of matrix metalloproteinase-2 mRNA (MMP-2 mRNA), tissue inhibitor of matrix metalloproteinase-2 mRNA (TIMP-2 mRNA), matrix metalloproteinase-2 protein (MMP-2), matrix metalloproteinase-9 protein (MMP-9), tissue inhibitor of matrix metalloproteinase-1 protein (TIMP-1), and tissue inhibitor of matrix metalloproteinase-2 protein (TIMP-2) in the hepatocellular carcinomas (HCCs).

Methods: Fifty-six specimens of HCCs from 56 patients, who were followed-up, were investigated by in situ hybridization with specific probes for MMP-2, TIMP-2, and by immunohistochemistry with anti-MMP-2, MMP-9 and anti-TIMP-1, TIMP-2 monoclonal antibody. We analyzed the data with chi-square test, spearmans correlation analysis, monovariate Kaplan-Meier plot and multivariate Cox regression analysis.

Results: 1. The positive expression of MMP-2mRNA, TIMP-2mRNA, MMP-2 protein, MMP-9 protein, TIMP-1 protein and TIMP-2 protein in the 56 HCCs cases were 48 (85.7%), 35 (62.5%), 44 (78.6%), 41 (73.2%), 30 (53.6%), and 38 (68%), respectively. 2. We found over-expression of MMP-2 mRNA, MMP-2 protein, and MMP-9 protein, but low expression of TIMP-1 protein in the 56 cases of HCCs (P < 0.01, P < 0.05). 3. There was a positive association between TIMP-2mRNA and TIMP-2 protein expression, and between MMP-2 mRNA and MMP-2 protein in HCCs, respectively (r = 0.316, P < 0.05; r = 0.356, P < 0.05). 4. Over-expression of MMP-2 mRNA was positively correlated to the tumor size and TNM classification (r = 0.441, P < 0.001; r = 0.340, P < 0.05), and MMP-9 protein was related to shortened survival (P < 0.05). 5. In both monovariate Kaplan-Meir plot and multivariate Cox regression analysis, the expression of MMP-2 protein and MMP-9 protein were linked to unfavorable prognosis. These results were further confirmed by multivariate analysis in which MMP-2 protein and MMP-9 protein emerged as independent prognostic factors for poor survival regardless of the age, tumor size, tumor grades, TNM classification and expression of MMP-2mRNA, TIMP-2mRNA, TIMP-1 protein and TIMP-2 protein. The hazard ratios of expression of MMP-2 protein and MMP-9 protein were 3.875 and 4.528, respectively.

Conclusion: The over-expression of MMP-2mRNA, MMP-2 protein and MMP-9 protein and the imbalance between MMP-2 and TIMP-2 play pivotal roles in the degradation of excellular matrix of HCCs. MMP-2 and MMP-9 immunoreactive protein have been closely related to a shortened survival independent of major prognostic indicators in the primary HCC and increase the risk of the patients after the operation.