Like many cancers, the development of breast cancer remains a mystery to health care professionals.  Why do some women get the disease, while others don't?  Sure, risk factors such as genetics, age, obesity, and lack of physical activity play a role, but overall these factors are only responsible for a small percentage of new breast cancer diagnoses. For the remaining cases, breast cancer researchers have been at a loss to determine why certain women seem to be more susceptible to the disease than others.

According to the American Cancer Society, one of every eight women in the United States is diagnosed with breast cancer during her lifetime, and more than 232,000 new cases of the disease are diagnosed annually.  Hundreds of studies have been conducted to date exploring the possibility of environmental risk factors for breast cancer development, but so far the results have been inconclusive.  For example, some research has found a link between breast cancer and the banned pesticide DDT, while others have found no link at all.  BPA is another chemical that has been cited as a possible breast cancer cause, but again, researchers have not found conclusive evidence of the link.  

But researchers are beginning to understand the timing of a woman's chemical exposure might be just as important - or even more so - than the type of chemicals that find their way into her body.  According to researchers, a  woman’s breast goes through three distinct periods of development - in the womb, during puberty, and in pregnancy.  Understanding the effect of chemical exposure at these critical times of breast tissue change may help to unlock the mystery behind breast cancer development.

“As researchers looking at adult outcomes of disease processes such as breast cancer, one of the biggest challenges we face is trying to get a handle on prenatal exposures and what is going on in the prenatal environment,” said Shanna Swan, an environmental health scientist at Mount Sinai School of Medicine in New York according to a new report by Environmental Health News.

That's why Barbara Cohn and colleagues at the Public Health Institute are testing the frozen blood samples of more than 100 women who enrolled in the Child Health and Development Studies nearly five decades ago to examine each woman's chemical exposures during the critical breast development period of pregnancy and compare these results to the participants' later health records.  The blood samples were taken from pregnant women in the Kaiser Permanente Health Plan in the Oakland, Calif., area who gave birth between 1959 and 1967.  Cohn and her team are looking for traces of dozens of pollutants that might cause breast cancer, hoping to discover which chemicals, when present at a woman's critical period of breast development, could trigger cancer decades later.  Researchers have also begun testing the daughters and granddaughters of the women in the initial study in order to get an even better idea of how the timing of various chemical exposures could affect a woman's health.  

And they are hopeful that this new strategy of studying the timing of exposure as well as the chemicals involved, might once and for all unlock the mysteries of breast cancer development.

via: Environmental Health News

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