[Regulation of tumor metastasis and extracellular matrix degradative enzyme production by microenvironments]

We have recently established human tumor cell lines which metastasize to specific organs from orthotopic implantation sites but not from ectopic sites in nude mice. Using these tumor cell lines we have been studying the mechanisms of the regulation of tumor metastasis by organ specific microenvironments. Here, we discuss the mechanisms of the regulation of extracellular matrix degrading enzyme production by interactions between tumor cells and tissue specific fibroblasts.