Fight Aging!

The general view of cancer is that it occurs in the old because it depends on nuclear DNA mutations that accumulate over time - the more mutations, the greater the chance of one of them being suitable to trigger a cancer. Here a researcher argues that it has less to do with the number of mutations and more to do with the changing (and more damaged) state of tissue and systems in the body, which increases the ability of mutated cells to survive and prosper: "For evidence, DeGregori points first to the fact that by the time we stop growing in our late teens, we've already accumulated a large fraction of the mutations we will have in our lifetimes. 'There's a mismatch between the mutation curve and the cancer curve,' DeGregori says, meaning that if cancer were due to reaching a tipping point of, say, five or six mutations, we should see higher cancer rates in 20-year-olds, as this is when mutation rate is highest. Second, DeGregori points out that even healthy tissues are full of oncogenic mutations. 'These mutations are many times more common than the cancers associated with them,' DeGregori says. Simply, more mutations doesn't equal more cancer - not across the aging population and not even in specific tissues. DeGregori's final two points come from evolution. As we've evolved from one-celled, short-lived life forms into multicellular, long-lived humans, we've had to develop complicated machinery to maintain our tissues and avoid disease. 'But we're no better at preventing mutations than our yeast or bacteria cousins. You'd think if avoiding mutations was key to avoiding cancer, we'd be better at it than we are.' And finally, if these oncogenes were the evil super-villains they've been made out to be, capable of taking over surrounding tissue, then introducing oncogenes into mice stem cells should help rather than hurt these cells' survival. 'Rather, stem cells harboring the oncogenes tend to get weeded out,' says DeGregori. Instead of gathering mutations until they give us cancer, DeGregori says that as we age, the mechanisms that younger adults use to fight cancer, deteriorate. ... Our healthy cells are optimized for the conditions of our healthy, younger tissue. Change this balance, as does an oncogenic mutation, and they're no longer a perfect fit for the surroundings - healthy cells in young bodies quickly outcompete cells with cancerous mutations. But, 'when tissue is old, healthy cells are no longer a perfect fit, and mutations might help a cancer cell adapt in ways a healthy cell can't,' DeGregori says."

Link: http://www.eurekalert.org/pub_releases/2012-07/uocd-wcr062812.php