The haematogenous spread of tumor: a prevental process.

The establishment of a secondary tumor is the outcome of a series of biological events. Cells detach from the primary tumor and penetrate vascular channels, which they leave again at a distant site to implant and proliferate in an organ or tissue remote from the primary tumor. These processes depend on the adhesion of tumor cells to each other, on the permeability of the venous or lymphatic channels and on the susceptibility of the substrate. Present experiments show that these properties are modifiable and that haematogenous tumor dissemination is a preventable process.