Biology of tumor micrometastasis

Metastasis is the major cause of death in cancer patients. Our understanding of the molecular genetic and biologic events that contribute to tumor cell dissemination has increased considerably over the last decade. It is clear that close anatomic and temporal cooperation between cellular adhesion molecules, extracellular matrix-degrading proteases, and tumor vascularization is an essential component of the metastatic behavior of cancer cells. With this improved understanding have come novel antimetastatic therapies targeting distinct molecules and steps in the metastatic cascade. Here, we review the role of matrix-degrading enzymes, changes in cellular adhesive capacity, and tumor angiogenesis during cancer spread.