Most cancer mutations arise from “bad luck”
It was the study that launched hundreds of scientific rebuttals, insinuations that the authors had been paid off by the chemical industry, and charges that it was a “massive” stunt “hidden behind fancy numbers of doubtful quality.”
The claim that sparked this controversy? That “bad luck,” more than environmental factors or inherited genes, affects whether someone develops cancer, implying that preventive efforts from smoking cessation to environmental cleanups were largely pointless.
Now the authors of that 2015 paper are back. In a study published on Thursday in Science, they double down on their original finding but also labor mightily to correct widespread misinterpretations of it. This time, using health records from 69 countries, they conclude that 66 percent of cancer-causing genetic mutations arise from the “bad luck” of a healthy, dividing cell making a random mistake when it copies its DNA.
No, We Can’t Say Whether Cancer Is Mostly Bad Luck
ED YONG, The Atlantic, MAR 28, 2017
Scientists have published new research that suggests up to 60% of cancers could be caused by random DNA mutations, rendering those cancers completely unavoidable. The other 40%, however, could be prevented via diet, exercise, and other environmental factors. Some parts of the body, like the skin or large intestine, are much more prone to cancer than others, like the brain or small intestine. The lifetime risk of developing cancer in a particular tissue was strongly correlated with how often the stem cells in that tissue divide (stem cells are the cells that renew our bodies by dividing indefinitely).
They argued that the random mutations arising in dividing stem cells represent a third group—distinct from the other two, more important, and unlikely to be preventable. When they published their results in the journal Science, they wrote:“These results suggest that only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions. The majority is due to “bad luck,” that is, random mutations arising during DNA replication in normal, noncancerous stem cells.”
Above statements would have been completely uncontroversial, had the scientists not framed their results in terms of “bad luck.” Some cancer-causing mutations are inherited, while others are inflicted upon our DNA by environmental risks like tobacco, sunlight, alcohol, or asbestos.