Expression of the extracellular matrix metalloproteinase inducer (EMMPRIN)and the matrix metalloproteinase-2 in bronchopulmonary and breast lesions

Tumor cells interact with stromal cells via soluble or cell-bound factors s timulating the production of matrix metalloproteinases (MM Ps), a group of enzymes largely involved in the extracellular matrix (ECM) remodeling in tu mor invasion. Among these factors, extracellular matrix metalloproteinase i nducer (EMMPRIN) has been shown to stimulate in vitro the fibroblast produc tion of Various MMPs such as interstitial collagenase (MMP-1), stromelysin- l (MMP-3), and gelatinase A (MMP-2). In this study, the EMMPRIN protein was detected by immunohistochemistry prominently in malignant proliferations o f the breast and the lung. It was present at the surface of both tumor epit helial and peritumor stromal cells. Because previous studies have reported that stromal cells do not express EMMPRIN mRNAs, it is very likely that EMM PRIN is bound to stromal cells via a specific receptor. Moreover, our obser vations also demonstrated that the same peritumor stromal cells strongly ex press MMP-2. Our results show that EMMPRIN is an important factor in tumor progression by causing tumor-associated stromal cells to increase their MMP -2 production, thus facilitating tumor invasion and neoangiogenesis.