A phenotype from tumor stroma based on the expression of metalloproteases and their inhibitors, associated with prognosis in breast cancer

The objective of the present work was to evaluate the impact of the phenotype of both mononuclear inflammatory cells (MICs) and cancer-associated fibroblast (CAFs) in early breast cancer patients, specifically assessed as to their expression of MMP/TIMP relative to their position within the tumor (i.e., localization at the tumor center or invasive front) and the occurrence of distant metastases.. An immunohistochemical study was performed using tissue arrays and specific antibodies against matrix metalloproteinase (MMP)-1, -2, -7, -9, -11, -13 and -14, tissue inhibitors of metalloproteinase (TIMP)-1, -2 and -3, both at tumor center and at invasive front, in 107 patients with primary ductal invasive breast tumors. Data were analyzed by unsupervised hierarchical clustering analysis. Our results indicated that MMP-11 expression by MICs, and TIMP-2 expression by CAFs at either the tumor center or the invasive front, were the most potent independent prognostic factors for predicting the clinical outcome of patients. Using the unsupervised hierarchical clustering analysis, we found well-defined clusters of cases identifying subgroups of tumors showing a high molecular profile of MMPs/TIMPs expression by stromal cells (CAFs and MICs), both at the tumor center and at the invasive front, which were strongly associated with a higher prevalence of distant metastasis. In addition, we found combinations of these clusters defining subpopulations of breast carcinomas differing widely in their clinical outcome. The results presented here identify biologic markers useful to categorize patients into different subgroups based on their tumor stroma, which may contribute to improved understanding of the prognosis of breast cancer patients.