A team of researchers from Stony Brook University, 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 behaviors weigh heavily on the development of a vast majority (approximately 70 to 90 percent) of cancers.
Recent research has highlighted a strong correlation between tissue-specific cancer risk and the lifetime number of tissue-specific stem-cell divisions. Whether such correlation implies a high unavoidable intrinsic cancer risk has become a key public health debate with the dissemination of the ‘bad luck’ hypothesis. Here we provide evidence that intrinsic risk factors contribute only modestly (less than ~10–30% of lifetime risk) to cancer development. First, we demonstrate that the correlation between stem-cell division and cancer risk does not distinguish between the effects of intrinsic and extrinsic factors. We then show that intrinsic risk is better estimated by the lower bound risk controlling for total stem-cell divisions. Finally, we show that the rates of endogenous mutation accumulation by intrinsic processes are not sufficient to account for the observed cancer risks. Collectively, we conclude that cancer risk is heavily influenced by extrinsic factors. These results are important for strategizing cancer prevention, research and public health.
While healthy habits like not smoking, keeping a healthy weight, eating a healthy diet and cutting back on alcohol are not a guarantee against cancer, they do dramatically reduce the risk of developing the disease.
Sources and press media releases
- Study Reveals Environment, Behavior Contribute to Some 80 Percent of Cancers, Stony Brook University, NY, December 16, 2015.
- Substantial contribution of extrinsic risk factors to cancer development, nature, 16 December 2015.
- Environmental factors increase risk of some types of cancer, study finds, theguardian, 18 December 2015.
- Cancer is not just ‘bad luck’ but down to environment, study suggests, BBC News health-35111449, 17 December 2015.
- Nine in 10 cancers caused by lifestyle, telegraph, 17 Dec 2015.