No. 107: Sep-Oct 1996
It has been generally believed that most cancers originate in a single founder cell, which then multiplies to create the tumor. But cancer is more insidious than expected. A precancerous founder cell may actually subvert nearby noncancerous cells and turn them into cancerous cells. In this sense, the first precancerous cell recruits and transforms healthy cells, enlisting them in its destructive operations, and thereby turning them against the body that produced them. No one yet knows how this subversion is effected or how it evolved. (Why is there cancer anyway?)
The basis for this claim involves a few rare human mosaics, whose bodies are built of cells with two different genetic complements. Cancers in human mosaics have been found to contain both types of cells and, therefore, did not grow from a single cell alone.
(Day, Michael; "Cancer's Many Points of Departure," New Scientist, p. 16, June 1, 1996)
Comments. Curiously, some "primitive" animals, such as sharks, seem to have evolved defenses against cancer that mammals lack. With reference to "mosaics," see item in SF#105 on "Mixed-Up People." Also relevant is BHH25 "'Insidious' Properties of Cancer Metastases" in Humans II. For information on this book, visit here.