| This is a hotly debated issue. Although there are no definitive studies demonstrating that occupational, environmental, or chemical exposures increase breast cancer risk, there is a mounting body of evidence suggesting that there may be a link.
 
 Exposure to the pesticide DDT is thought to increase the risk of breast cancer, because its breakdown products mimic the effects of estrogen in the body.  Prolonged estrogen exposure is a known risk factor for breast cancer.  Consumption of food from animals that have been injected with hormones (including estrogen) to speed their growth may also be a risk factor.
 
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