Two cellular “clocks” that tick-tock synchronically with the process of ageing and the progress of cancer have been discovered by a team of researchers from the UK and the US led by scientist Michael Stratton. The paper, entitled “clock-like mutational processes in human somatic cells”, is published in the journal Nature Genetics.
Michael Stratton and his colleagues have laid their hands on two “clocks”, each displaying a specific function.
The scientists analysed the DNA sequencing of over 10,000 different cancer cases spanning over 36 types of diseases, searching for mutation patterns called ‘signatures’ via computer algorithms. That was how they found two signatures whose progress rhymed with the monotonous “tick-tock” of clocks; these are DNA mutations that undergo progress at a regular rate.
A correlation was found between the number of mutations (of both signatures) and the age of the person whose tissue was studied. The researchers, therefore, concluded that these cell clocks might be associated with the process of ageing.
Stratton explains in New Scientist that while mutations normally happen throughout one’s life, certain combinations occur in some individuals that ultimately lead to the development of cancer. Stratton believes if mutation rates are different from person to person, the progression speed can be determined to be able to forecast the point in time at which the mutations will cause cancer – but, this yet have to be proved.
What he did achieve though was to go back in the past: the team calculated the time at which the mutations began and of their eventual development.
Their findings might pave the way to calculate the speed of cancer propagation which could help with treatment plans. They also have implications in the process of ageing.
“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,” co-author Ludmil Alexandrov said in a 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.”