Scientists have made a genetic breakthrough which they claim could extend human life and even protect against cancer.
They carried out experiments on mice which made them live 45 per cent longer and left them free from tumours.
The researchers are confident that the technique could be used to extend the lifespan of humans - perhaps within 20 years - because the genes involved exist naturally in both mice and humans and perform similar roles.
And they say that the breakthrough could one day see all humans benefiting from a longer and healthier life without the threat of serious disease.
Leading geneticists and cancer experts say the development is both extraordinary and exciting.
The team of researchers achieved their results by inserting an extra copy of three genes - called telomerase, p53 and p16, already known to be important for longevity and suppressing tumours - into the stem cells of mice.
Inserting an extra copy improves their function in the body because they produce more protein, which makes them more active.
This in turn helps telomerase to protect chromosomes from shrinking, a process which normally happens naturally as all living creatures age. And it means p53 and p16 work to prevent cells mutating and dividing - and therefore preventing cancer - while producing a good balance of new and healthy cells.
Key to long life: Tests on mice have helped scientists discover the way to extending the human lifespan
The technique is groundbreaking because it managed to get extra copies of both p53 and p16 into the mice, which scientists have been trying to do for years. It is also the first time that scientists have been able to extend the life of mice in this way while protecting them against cancer.
Previously, mice had been bred to be cancer-free but their lifespans were not significantly altered. In some cases, they were shortened. Scientists have previously extended the life of mice but only by restricting their diet.
The modified mice were allowed to breed to strengthen their new DNA pattern, which created a group of ‘supermice’ with longer lifespans and in-built cancer protection.
It is thought the researchers managed to create mice which lived to around four-and-a-half years. Normally, they live for an average of three years.
The team, from the Spanish National Cancer Research Centre (CNIO) in Madrid, say this is the equivalent of humans living to 125.
Manuel Serrano, one of the researchers speaking at a conference, said: ‘When activating p53 and p16 in mice, the incidence of cancer is reduced to practically zero.
'We don’t think the mice lived longer because they had less cancer but because these genes also protected against ageing.’
Chief researcher Maria Blasco, one of Spain’s leading scientists, told the conference: ‘The elixir of eternal youth is now not a utopian dream.
‘The discovery opens the door to [the possibility] that humans could live 125 years and without cancer.’
Top British geneticist Aubrey de Grey called it an ‘extraordinary breakthrough’ which scientists had been trying to achieve for years.
He added: ‘The big thing that makes this new is that it’s the first time anyone has succeeded in manipulating the interaction between cancer and ageing in a manner that actually succeeds and produces a longer lifespan in mammals than would exist without intervention.’
