Resistance to cancer and increased longevity are thought to be flip sides of the coin when it comes to variations in metabolism and the controlling mechanisms of stem cell action. Either your cells are more ready to divide and repair your tissues, in which case you have increased longevity coupled with increased risk of cancer, or your cells are less ready to divide and repair your tissues and as a consequence you are less likely to suffer cancer, but also less likely to live for as long as your contemporaries in the scenario under which you do evade cancer. The decline of stem cell capacity with age is thought to be an adaptation to resist the increasing risk of cancer due to rising levels of cellular and molecular damage - the less that your stem cells take action, the less likely it is that a cancerous mutation will occur and take hold.

Cancer is a game of odds, in other words. We're all rolling those dice, day in and day out - regardless of how indifferent we are or pretend to be. It's a sobering thought.

On this topic, I noticed an intriguing twin study today that suggests the naturally longer-lived humans amongst us are having their cake and eating it too when it comes to the supposed cancer-longevity balance. There's no balance here at all, just benefits all round from happening to be naturally longer-lived:

BACKGROUND: Animal models and a few human studies have suggested a complex interaction between cancer risk and longevity indicating a trade-off where low cancer risk is associated with accelerating aging phenotypes and, vice versa, that longevity potential comes with the cost of increased cancer risk. This hypothesis predicts that longevity in one twin is associated with increased cancer risk in the cotwin.

METHODS: A total of 4,354 twin pairs born 1900-1918 in Denmark were followed for mortality in the Danish Civil Registration System through 2008 and for cancer incidence in the period 1943-2008 through the Danish Cancer Registry.

RESULTS: The 8,139 twins who provided risk time for cancer occurrence entered the study between ages 24 and 43 (mean 33 years), and each participant was followed up to death, emigration, or at least 90 years of age. The total follow-up time was 353,410 person-years and 2,524 cancers were diagnosed. A negative association between age at death of a twin and cancer incidence in the cotwin was found in the overall analyses as well as in the subanalysis stratified on sex, zygosity, and random selection of one twin from each twin pair.

CONCLUSIONS: This study did not find evidence of a cancer-longevity trade-off in humans. On the contrary, it suggested that longevity in one twin is associated with lower cancer incidence in the cotwin, indicating familial factors associated with both low cancer occurrence and longevity.

It's worth remarking that the ultimate goal for longevity science is to make this and all similarly interesting discoveries absolutely irrelevant - to create a world in which it no longer matters in the slightest which genes we are born with. Sufficiently advanced medical technology - such as that envisaged in the Strategies for Engineered Negligible Senescence, which could be produced within the next twenty to thirty years given the funding - will enable all people to live extremely long lives in good health regardless of their genetic heritage. This is all the more reason to support that research; doing something about the limitations of the human condition beats sitting around listening to the dice roll and your chances of cancer inch upward year by year.

Source:
http://www.longevitymeme.org/newsletter/latest_rss_feed.cfm