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Researchers at Stony Brook University explain that about 70 to 90 percent of cancers are impacted by external factors such as "behavior and environment", which could impact how we treat cancer and make us create 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.

Four methods were used to assess the risk of cancer, making them find collectively as well as individually, that just ten to 30 percent of cancers are due 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."

In their first approach, the scientists examined extrinsic risks by assessing the tissue turnover. They looked at the quantitative relationship between "the division of normal tissue stem cells and lifetime cancer risk".

Secondly, they took up mathematical models in order to survey and analyze studies on cancer mutation signatures.

Thirdly, they analyzed data on Surveillance, Epidemiologic and End Results Program (SEER) and finally employed "computational modeling" in order to analyze the contribution of intrinsic processes that led to the development of cancer.

Hannun believes that the 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 Dec. 16 issue of Nature.