Scientists from the UK and USA have identified two 'clocks' found in almost every cell in our bodies: they measure the rate at which we age and our chances of getting cancer respectively, researchers say.
Not only could the discovery improve our understanding of ageing and disease, it might also help us prevent cancer and even slow down the process of growing old, if these clocks can be slowed down in some way.
The research was led by Michael Stratton of the Wellcome Trust Sanger Institute, as New Scientist reports. Together with a team of colleagues, Stratton looked at the DNA sequencing in more than 10,000 different cases of cancer covering 36 different types of the disease.
Using computer algorithms the researchers looked for patterns in the mutations – known as 'signatures' – and found two that progressed with the steady 'tick-tock' monotony of clocks.
While some DNA mutations occur in bursts (from smoking or sun exposure for example), others move forward at a more regular rate, and it's these mutations the Cambridge scientists were looking for. For both signatures, the number of mutations correlated with the age of the person the tissue came from, so it looks like there's a link to be found between these cell clocks and the way that our bodies age.
"It's not an inevitability for an individual to get cancer, but it's an inevitability for us as a species," Stratton explained to New Scientist. "We accumulate mutations over a lifetime and in some people the correct combination leads to a cancer emerging. Further research will discover if our mutation rates differ between individuals. If that is the case, the expectation would be that those rates could be read out to predict the time they might take to become cancerous."
Stratton and his team were able to analyse cancerous cells to effectively look back in time, working out when the mutations started and how they developed. Ultimately, these findings may help doctors work out how quickly a cancer is going to spread around the body or which drugs are going to be resistant to it, enabling them to put together more personalised treatment plans for each of their patients.
"This is a hugely exciting finding as it solves a longstanding question. Not only has this study proved that mutational molecular clocks exist, it has also shown that there are two separate clock processes that are constantly degrading DNA," said report co-author Ludmil Alexandrov in a press statement. "How fast these clocks tick in a cell may well determine both the ageing of this cell and the likelihood for it to become cancerous."
The team's work has now been published in the journal Nature Genetics.