Significance of membrane type 1 matrix metalloproteinase expression in breast cancer

Expression of matrix metalloproteinases (MMPs) plays an essential role in t umor metastasis and invasion through the degradation of extracellular matri x (ECM). MT1-MMP (membrane type 1 matrix metalloproteinase), a membrane-typ e MMP, is responsible for the activation of MMP2. In this study the signifi cance of MT1-MMP expression in human breast tumors was investigated by immu nocytochemical assay, and its correlation with clinicobiological features w as analyzed, MT1-MMP expression was detected in tumor cells and/or stromal cells, and there was a strong correlation between the expressions of MT1-MM P in the two cell types. Out of 183 primary tumors, 103 (56.2%) showed posi tive staining of MT1-MMP in tumor cells, MT1-MMP expression showed no signi ficant correlation with any of the clinicobiological parameters examined, i ncluding hormone receptor status and angiogenesis, In postoperative surviva l analysis, MT1-MMP expression itself was not a significant prognostic fact or. However, in the particular subgroup with the accumulation of thymidine phosphorylase (TB)-positive stromal tells, which have been activated by var ious stimuli, such as cytokines and hypoxia, MT1-MMP expression had a signi ficant prognostic value, These data suggested that MT1-MMP might function c ooperatively with tumor-associated stromal cells for the progression of bre ast cancer.