Despite previous findings that say otherwise, a recent study by researchers at Stony Brook University proposes that approximately 70 to 90 percent of cancers are influenced by extrinsic factors such as behavior and environment. The results could force us to change how we treat cancer and stimulate the creation of new diagnosis and treatment methods.
"Cancer is caused by mutations in the DNA of cells, which leads to uncontrolled cell growth instead of orderly growth. But the development of cancer is a complex issue, and we as a scientific community need to have solid analytical models to investigate what intrinsic and extrinsic factors cause certain forms of cancer," Yusuf Hannun, senior author of the paper, said in a press release.
The researchers used four approaches to assess cancer risk and discovered that both collectively and individually, only ten to 30 percent of cancers are attributed to intrinsic factors.
"Many scientists argued against the 'bad luck' or 'random mutation' theory of cancer but provided no alternative analysis to quantify the contribution of external risk factors," said Song Wu, lead author of the paper. "Our paper provides an alternative analysis by applying four distinct analytic approaches."
The first approach consisted of examining extrinsic risks by looking at tissue turnover by reexamining the quantitative relationship between the division of normal tissue stem cells and lifetime cancer risk. Second, they used mathematical models to survey and analyze studies on currently known cancer mutation signatures. Third, they analyzed Surveillance, Epidemiologic and End Results Program (SEER) data and finally used computational modeling to analyze the contribution of intrinsic processes in the development of cancer.
Hannun believes that their results offer a "new framework to quantify the lifetime cancer risks from both intrinsic and extrinsic factors, which will have important consequences for strategizing cancer prevention, research and public health."
The findings were published in the Dec. 16 issue of Nature.
