Researchers have challenged the idea that most cases of cancer are "bad luck."
The idea comes from studies of DNA mutation rates. These have suggested that mutation rates may vary from organ to organ, helping to explain why some organs are more vulnerable than others to disease.
But a new study claims that mutation rates are constant among organs.
The Dutch researchers studied DNA mutations in stem cells from the colon, small intestine and liver.
Reporting in Nature, they say that each type of stem cell experienced about 40 mutations a year. This was not affected by the nature of the organ or the age of the patient.
However they also found differences in the types of mutation between tissues.
The researchers say the findings "debunk" the idea that different cancer rates for different organs are largely the result of varying DNA mutation rates.
Researcher Dr Ruben van Boxtel, of UMC Utrecht, the Netherlands, said: “We were surprised to find roughly the same mutation rate in stem cells from organs with different cancer incidence,” says Dr Ruben van Boxtel, lead researcher of the team.
“This suggests that simply the gradual accumulation of more and more ‘bad luck’ DNA errors over time cannot explain the difference we see in cancer incidence – at least for some cancers.”
Dr Lara Bennett, of Worldwide Cancer Research, which backed the study, said: “Some organs are more prone to developing tumours than others. For example as many as 110 new cases of bowel cancer are diagnosed every day in the UK, compared to just 15 cases of liver cancer.
“Lifestyle factors such as smoking and diet can account for part of the difference in cancer incidence, but researchers don’t yet fully know why some types of cancer are more common.
"This new research by Dr van Boxtel and his group is important because it provides actual measured data on the rate of DNA error accumulation in human stem cells for the first time, and shows that perhaps not as much cancer risk is down to this type of ‘bad luck’ process as has recently been suggested.”
Blokzijl et al. Tissue-specific mutation accumulation in human adult stem cells during life. Nature 3 Oct 2016 [abstract]
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