Seventy percent to ninety percent of cancer results from avoidable factors such as toxic chemicals and radiation, according to a new research published in the journal Nature. The new findings contradict earlier reports about two-thirds of cancer are mainly due to bad luck.

The researchers argued that if bad luck, brought by intrinsic factors, played a major role in cancer development, then the total number of stem cell divisions would correlate with the total cancer risk. However, this instance is uncommon. The team said that only 10 percent to 30 percent of cancer result from intrinsic factors.

Researchers also analysed the extent to which 30 distinct signatures or fingerprints among different cancers are triggered by intrinsic or extrinsic factors. The team found that most cancers. including lung, bladder, thyroid and colorectal cancers, are caused by extrinsic factors including lifestyle and environment. Only few cancers arise from intrinsic mutations.

Moreover, the researchers also found out that people who moved from countries with low cancer rates to countries with high cancer rates quickly acquired a higher cancer risk, indicating that extrinsic factors are at fault. These findings are important to strategising cancer prevention, research and public health.

Medical News Today reported earlier that bad luck causes 65 percent of cancer cases due to random DNA mutations, while the remaining 35 percent are caused by a combination of these mutations and environmental or hereditary factors. But the new study says that people can no longer smoke excessively then simply blame bad luck for causing lung cancer.

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