Did Cancer Evolve to Protect Us?
Could cancer be our cells’ way of running in “safe mode,” like a damaged computer operating system trying to preserve itself, when faced with an external threat? That’s the conclusion reached by cosmologist Paul Davies at Arizona State University in Tempe (A.S.U.) and his colleagues, who have devised a controversial new theory for cancer’s origins, based on its evolutionary roots. If correct, their model suggests that a number of alternative therapies, including treatment with oxygen and infection with viral or bacterial agents, could be particularly effective.
At first glance, Davies, who is trained in physics rather than biomedical science, seems an unlikely soldier in the “war on cancer.” But about seven years ago he was invited to set up a new institute at A.S.U.—one of 12 funded by the National Cancer Institute—to bring together physical scientists and oncologists to find a new perspective on the disease. “We were asked to rethink cancer from the bottom up,” Davies says.
Davies teamed up with Charley Lineweaver, an astrobiologist at The Australian National University in Canberra, and Mark Vincent, an oncologist at the London Health Sciences Center in Ontario. Together they have come up with an “atavistic” model positing cancer is the reexpression of an ancient “preprogrammed” trait that has been lying dormant. In a new paper, which appeared in BioEssays in September, they argue that because cancer appears in many animals and plants, as well as humans, then it must have evolved hundreds of millions of years ago when we shared a common single-celled ancestor. At that time, cells benefited from immortality, or the ability to proliferate unchecked, as cancer does. When complex multicellular organisms developed, however, “immortality was outsourced to the eggs and sperm,” Davies says, and somatic cells (those not involved in reproduction) no longer needed this function.
The team’s hypothesis is that when faced with an environmental threat to the health of a cell—radiation, say, or a lifestyle factor—cells can revert to a “preprogrammed safe mode.” In so doing, the cells jettison higher functionality and switch their dormant ability to proliferate back on in a misguided attempt to survive. “Cancer is a fail-safe,” Davies remarks. “Once the subroutine is triggered, it implements its program ruthlessly.”