Most of the deaths from human cancers (90%) are due to cancer cells spreadingand establishing colonies in other parts of the body.
Robert Weinberg, Ph.D
Whitehead Institute for Biomedic Research
Cancer cells also have to learn how to invade and metastasize. And that, in fact,is involved in the inactivation of a whole series of controls that normally confinesa cell to the site and the tissue where it normally grows – enabling thesecells to move to other sites in the body.
In 2000, Douglas Hanahan (shown below) and Robert Weinberg published a paperin Cell, "The Hallmarks of Cancer," which identified some organizingprinciples of cancer cell development.
Cancers kill you, in general, not just because they grow into a large lump, butbecause they invade into normal tissues and disrupt the functions of those tissuesand they develop the ability to migrate to distant sites in the body. And thesecapabilities of invasion and metastasis, which are very closely linked but perhapshave separable aspects as well, are very important for the fatality of most cancers.And this is the one that's perhaps least connected to simple cell growth andaccumulation of the cells, but actually are producing cells that really are ableto sustain themselves, expand, and migrate.