During complex process of tumor metastasis, tumor cells interact with various extracellular matrix proteins. These proteins regulate tumor invasion and metastasis positively or negatively. Tumor cells utilize various types of matrix-degrading proteinases to invade through basement membranes and connective tissues. These matrix proteinases are classified into two major groups: the matrix metalloproteinases (MMPs) such as gelatinases A and B, interstitial collagenase, stromelysin, matrilysin and MT-MMPs, and the matrix serine proteinases such as plasminogen activators, plasmin and trypsin. On the other hand, we have found laminin-5 (ladsin) as a tumor-derived cell scattering factor with potent cell adhesion and cell motility activities. This protein is assumed to contribute to tumor cell migration. This article describes our recent results on functions of matrilysin, trypsin and laminin-5 in the malignant growth of tumor cells.
