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What are the top three causes of cancer?
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1.  Genetic predisposition – people who have a family history of cancer may be more likely to develop it.
2.  Tobacco use – smoking is one of the leading causes of lung cancer, and exposure to secondhand smoke can also increase your risk of developing this type of cancer.
3.  Radiation – radiation therapy for other cancers or medical treatments such as X-rays or CT scans can increase your risk of developing certain types of cancer.