Prenatal BPA or DES, breast cancer link

NEW HAVEN, Conn., May 28 (UPI) -- U.S. researchers have linked prenatal exposure to endocrine disrupting chemicals such as bisphenol A to breast cancer in mice.

The study, published in Hormones & Cancer, suggests exposure to endocrine-disrupting chemicals such as BPA and diethylstilbestrol, or DES, used in manufacturing may program a fetus for life.

"BPA is a weak estrogen and DES is a strong estrogen, yet our study shows both have a profound effect on gene expression in the mammary gland -- breast -- throughout life," lead author Dr. Hugh Taylor of the Yale University School of Medicine in New Haven, Conn., said in a statement.

"All estrogens, even 'weak' ones can alter the development of the breast and ultimately place adult women who were exposed to them prenatally at risk of breast cancer."

Taylor and colleagues treated pregnant mice with BPA or DES, looked at the offspring as adults and found their mammary glands still produced higher levels of EZH2 -- a protein that plays a role in the regulation of all genes. Higher EZH2 levels are associated with an increased risk of breast cancer in humans.

"We have demonstrated a novel mechanism by which endocrine-disrupting chemicals regulate developmental programming in the breast," Taylor said. "This study generates important safety concerns about exposures to environmental endocrine disruptors such as BPA and suggests a potential need to monitor women exposed to these chemicals for the development of breast lesions as adults."