Biomechanical interactions of cancer cells with the microvasculature during hematogenous metastasis.

Different aspects of hematogenous metastasis are discussed from the viewpoint of biomechanics. The processes considered include the role of primary tumor pressure, cell locomotor forces and degradation, in invasion of tissues and intravasation by cancer cells. Consideration of the fluid dynamics of cancer cell movement along capillaries lead to the view that in vivo, arrest is primarily due to mechanical trapping of cancer cells, and that the pathobiologic role of so-called adhesion molecules is not mainly in the arrest and adhesion of cancer cells, but rather in stimulating their proliferation by signal induction. As a consequence of deformation from spherical-to-cylindrical shape in the microvasculature, demands for increased surface membrane area leads to increases in surface membrane tension above critical levels for rupture, and the cancer cells are rapidly and lethally damaged. The possibility is briefly discussed of increasing the susceptibility of circulating cancer cells to mechanical trauma, as a form of anti-metastatic therapy.