Biology of metastasis: clinical implications

Bladder tumor has a spectrum of neoplastic activity. Some behave in a benign fashion, and others are highly aggressive and lead rapidly to metastatic disease and death. The processes of metastasis can be described as a sequence of interrelated steps. The processes involve 1) tumor cell adhesion to basement membranes, 2) the degradation of basement membranes, and 3) the migration of tumor cells through the destroyed stroma into blood and lymphatic vessels. Each of these processes involves the expression of molecular factors unique to tumor cells. With better understanding of the molecular basis of these factors, novel prognostic and potential therapeutic agents can be generated and applied to the clinical arena.