ABSTRACT
The specificity of intercellular interactions in the process of metastasis is responsible for targeted metastatic spread occurring only when the transplants are placed in specific organ locations, supporting the so-called “seed and soil” hypothesis of Paget. The process of cell adhesion is one of the critical determinants of site-specific metastasis. Screening patient specimens for genetic determinants in tumor cells responsible for such determinants may reveal a propensity to metastasis early in this process and, eventually, serve to develop specific antimetastatic tools. The bridging of the intracellular cytoskeleton with the extracellular matrix occurs through integrins and is cell type specific. Somatic cell hybridization and deoxyribonucleic acid (DNA) transfection experiments as well as the isolation of complementary DNA clones by subtractive hybridization point to the existence of metastasis suppressor genes that inhibit invasion and metastasis. The coordinated, highly localized, and multicomponent proteolytic activity of invading tumor cells is the intrinsic characteristic of metastatic tumors and is a focus of intense investigations.
