It’s long been thought that our cells stop dividing as we age as a natural preventative measure against cancer. Now a new study has found an intriguing piece of evidence supporting this hypothesis in genomes from several families that seem to be particularly prone to cancer.
In a way, our cells have a pre-determined number of divisions in their lifetime – around 50. That limit is dictated by our telomeres, small repeating segments of “junk” DNA that form caps on the ends of our chromosomes. These act like a buffer protecting the important DNA in the chromosomes from damage when a cell divides, but a little piece of the telomere is lost each time.
Eventually that damage adds up and the telomeres shorten to the point that the cell stops dividing. This contributes to the symptoms of aging that we’re all too familiar with.
In theory, lengthening our telomeres or preventing them from shrinking should help slow the aging process, or even reverse it. Indeed, plenty of research is investigating this angle. But there’s a nasty potential downside to doing so – cancer.