ABSTRACT
This chapter outlines biochemical processes which demonstrated to be of importance in cancer invasion, and describes laboratory methods that are likely to further the elucidation of these processes and demonstrate their clinical significance. A conspicuous function necessary for cancer cells to generate distant foci is the penetration of basal lamina, which must be achieved on two separate occasions. First, the tumor cells must create an entry into the blood or lymph by invasion through the basal lamina surrounding the capillary endothelial cells at the site of the primary tumor. Second, after attachment to the endothelial wall at a distant site, the tumor cells must once again traverse a basal lamina circumscribing the capillary. The expression of proteases and protease inhibitors may be integrally controlled within tissues in order to regulate the turnover of matrix proteins. Such interplay between proteases and their inhibitors may also have correlates in the metastatic cascade.
