A new study suggests that two-thirds of cancer cases can be put down to the bad luck of random DNA mutations rather than unhealthy lifestyles or inherited genes.
The new research, published in Science, finds that DNA mutations which accumulate throughout the body during cell division are the main reason for the development of cancer. The study suggests that just a third of cancers are the result of environmental factors, poor lifestyle or defective inherited genes.
The research, which brought together data from hundreds of existing research projects, considered 31 different types of cancer. It found that 22 of them—including testicular, ovarian, pancreatic, bone, and brain cancer—are largely explained by DNA mutations. In fact, they strongly correlated with the stem cell division rate of the affected tissue. The faster stem cells divides, the higher the chance in a given time period that random DNA mutations occur.
Another nine types of the disease—including lung, colorectal and skin cancer—were influenced by heredity and environmental factors. All told, the study suggests that 65 percent of cancers are a result of random mutation, meaning that they can be put down to plain old bad luck.
Professor Bert Vogelstein, a researcher from Johns Hopkins University School of Medicine who was involved in the research, said to the Guardian:
"All cancers are caused by a combination of bad luck, the environment and heredity, and we've created a model that may help quantify how much of these three factors contribute to cancer development. 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. The best way to eradicate these cancers will be through early detection, when they are still curable by surgery."
However, the researchers also warn that the finding isn't a reason for complacency , pointing out that poor lifestyle can contribute to the likelihood of developing cancer. Equally, the study didn't consider all cancer types, so there's only so far that the results can be extrapolated.
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