London –
Most cases of cancer are the result of “bad luck” rather than unhealthy lifestyles, diet or even inherited genes, claim scientists.
For 65 percent of cancer victims, the cumulative effect of random mistakes in genes is to blame for the disease.
Previously experts have estimated that 30-40 percent of cancer cases would be avoided given a better lifestyle, but there has been no similar calculation about whether the remainder can be prevented.
US researchers have now made the first attempt to quantify the proportion of cases that are unavoidable.
They looked at the random mistakes, or mutations, that occur in DNA when self-renewing stem cells divide during an average person’s lifetime.
The more of these mutations that accumulate, the higher the risk the cells will grow unchecked – the hallmark of cancer.
The researchers’ report, published in the journal Science, found that “bad luck” mutations which occur when one chemical letter in DNA is wrongly swapped for another during cell replication largely explained 22 of the 31 cancer types studied.
Co-author Professor Bert Vogelstein, from Johns Hopkins University School of Medicine in Baltimore, Maryland, said: “This study shows that you can add to your risk of getting cancers by smoking or other poor lifestyle factors.
“However, many forms of cancer are due largely to the bad luck of acquiring a mutation in a cancer driver gene regardless of lifestyle and heredity factors.”
Daily Mail