A Spreading Disease
A major reason that many cancers are so dangerous is that they metastasize. This means that instead of staying in one place, the cancer cells migrate from their original site to other parts of the body. No wonder, then, that scientists are busy studying the mechanism that enables cells to move around, in hope of finding a way to control this migration.
Whether it's an immune cell going off to battle infection, or a cancer cell making its way to a new area of the body, the underlying mechanism for its movement is the same. All non-blood cells are surrounded by a fibrous material known as the extracellular matrix. Cells on the go use a point-to-point adhesion system, which functions like tiny hooks, to grab the materials that make up the extracellular matrix. So basically, in order to move, a cell climbs hand-over-hand along the extracellular matrix until it reaches a blood or lymphatic vessel and penetrates it. From there, it's smooth sailing. By the way, the thinner walls of lymphatic vessels are easier to penetrate, which is why examining lymph nodes plays a major role in cancer detection.
Stopping Cancer In Its Tracks
The trick then, is not only to figure out all the factors that affect the chemical reactions that enable cells to move around, but also to figure out how to control these reactions selectively. Because cell movement is necessary for healing wounds and fighting off diseases, stopping it completely isn't an option. Instead, scientists will have to figure out how to block movement in select locations, like in the extra-cellular matrix around growing tumors.
"Cancer 'n' Car Keys" (Why Files)