BACKGROUND The activation of proMMP-2 is induced by membrane type 1-matrix metalloproteinase (MT1-MMP), but inhibited by tissue inhibitors of matrix metalloproteinase type 2 (TIMP-2). This study was carried out to establish the pattern of mRNA expression of MMP-2, MT1-MMP, and TIMP-2 in breast carcinomas. METHODS Seventy-nine cases of invasive ductal carcinoma, 10 of ductal carcinoma in situ, and 10 of fibrocystic disease as a control were analysed for the expression of MMP-2, MT1-MMP, and TIMP-2 mRNA, using in situ hybridization.
Correlations of the results with the clinical stage, tumor size, nodal status, and nuclear grade were analysed. RESULTS The expression rates of MMP-2, MT1-MMP, and TIMP-2 mRNA in invasive ductal carcinoma were 68%, 73%, and 56%, respectively. They were localized to both stromal and tumor cells, but mainly in the latter. The MMP-2 mRNA expression was significantly correlated with the clinical stage (p < 0.05), while the expression of TIMP-2 mRNA was inversely correlated with clinical stage and tumor size(p < 0.05).
Significant positive correlations between MMP-2 and MT1-MMP expressions, along with inverse relationships between MMP-2 and TIMP-2, and between TIMP-2 and MT1-MMP, were also found.
CONCLUSIONS: MMP-2 and TIMP-2 mRNA expressions might be useful as one of a range of prognostic parameters in breast carcinoma patients.