Stromal cell expression of components of matrix-degrading protease systems in human cancer.

Components of matrix-degrading protease systems are in human cancer often expressed by tumour-infiltrating stromal cells. The cellular pattern of expression of these molecules appears to be unique for each type of cancer. In several cases there are similarities with patterns observed in nonmalignant remodelling processes in the same tissue. These findings indicate that the stromal cells actively participate in the process of cancer invasion. The implications of this new paradigm for cancer biology and cancer treatment are discussed.