Research shows what causes up to 90 percent of cancer

Do you ever find yourself worried about what caused a loved one’s cancer or perhaps your own and want to get to the bottom of whether it might have been physiological or derived from external environmental risks?

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New research out this week has shown that 70 to 90 percent of cancers are caused by environmental factors in a frightening turnaround from research tabled earlier in 2015 that pointed to genetic factors.

A team of researchers from Stony Brook University, New York, led by Yusuf Hannun, MD, the Joel Strum Kenny Professor in Cancer Research and Director of the Stony Brook University Cancer Center, have found quantitative evidence proving that extrinsic risk factors, such as environmental exposures and behaviours weigh heavily on the development of a vast majority (approximately 70 to 90 percent) of cancers. The finding, reported in the December 16 online issue of Nature, in a paper titled “Substantial contribution of extrinsic risk factors to cancer development,” may be important for strategising cancer prevention, research and public health.

Inspired by a January 2015 research paper in Science, which concluded that the majority of the variation in cancer risk among tissues is due to “bad luck,” the Stony Brook team used the same data to assess what leads to the risk of developing cancer. And this team of scientists concluded the opposite – that most cancers are the result of external risk factors not because of internal or intrinsic factors of “bad luck”.

The scientists undertaking the study developed four distinct approaches to assess cancer risk. With these four approaches, they discovered collectively and individually that most cancers are attributed largely to external risk factors, with only 10-to-30 percent attributed to random mutations, or intrinsic factors.