Adhesion of tumor cells to matrices and endothelium

Cell adhesion is a process fundamental to tumor metastasis. Egress of cells from tumors and their entry into secondary tissues requires the regulated adhesion that underlies the process of cell migration. Thus, adhesion molecules must bind and release counter-receptors on the adhesive substrate in a controlled manner that permits locomotion (1-3). These same molecules must also interact in a complex manner with the intracellular actin cytoskeleton that is the motor for migration (1-3). In addition, it is now clear that there are interactions between adhesive counter receptors that do not mediate primary attachment to a substrate or support migration but are used to sample the adhesive microenvironment. Integration of "adhesive" signals with those from growth factors and cytokines may be used to regulate the pathophysiological responses of cells (1,4,5).