Most cancers caused by chance mutations
Scientists are always telling us what we can do to lower cancer risk: Exercise more, stay out of the sun, eat more of this and less of that. But new research suggests that two-thirds of cancer-causing genetic mutations are the result of random and unavoidable DNA errors—“bad luck,” as the authors put it. Mistakes occur every time a cell divides and copies its DNA to produce two new cells. Most of those mutations don’t c ause any harm, reports NBCNews.com, but a small number affect so-called cancer driver genes. After analyzing genome sequencing and epidemiologic data from 32 cancer types in 69 countries, researchers at Johns Hopkins University found that 29_percent of cancer-causing mutations are the result of environmental factors, such as smoking and sun exposure; 5_percent are caused by inherited genetic mutations; and 66_percent are completely random. They note that arbitrary mutations are more common in cancers involving tissues with higher rates of cellular “turnover,” such as the colon. Critics of the study contend that cancer is a complex disease whose causes cannot be separated and simplified, and that people shouldn’t be discouraged from quitting smoking and taking other steps that reduce their cancer risk. But the authors say their findings offer comfort and reassurance to the millions of people who have been diagnosed with cancer despite living a healthy lifestyle. “It’s not your fault,” says co-author Bert Vogelstein.