Interactions between tumor cells and vascular endothelium.-II) Light and electron microscopic studies.

Electron microscope technique was used to investigate the passage across the endothelial monolayer by murine tumor lines. After the initial adhesion, cancer cells induce a retraction of endothelium and migrate under vascular intima. Subsequently they spread on basement membrane showing a flattened shape, meanwhile endothelial cells reconstitute the monolayer. The four tumor lines show a similar behaviour being able to induce endothelial retraction and exposure of extracellular matrix and cross through the monolayer. The technique appears useful to study in details this multi-step process.