In Utero Exposure to Chemicals May Cause Breast Cancer
Mouse study implicates environmental chemicals DES and BPA in increased breast cancer risk
WEDNESDAY, June 9 (HealthDay News) -- Prenatal exposure to endocrine-disrupting chemicals found in the environment can cause overexpression of a protein linked to the development of breast cancer in adulthood, according to a mouse study published online May 15 in Hormones & Cancer.
Leo F. Doherty, M.D., of Yale University in New Haven, Conn., and colleagues treated pregnant mice with bisphenol-A (BPA) or diethylstilbestrol (DES), both estrogen-disrupting chemicals, in proportions consistent with human environmental exposure. When they reached adulthood, the female offspring were tested for the expression of enhancer of Zeste Homolog 2 (EZH2), a protein that has been linked to breast cancer risk in humans. The researchers also exposed the human breast cancer cell line MCF-7 to DES and BPA.
Mice exposed to DES in utero had a more than two-fold increase in EZH2 expression, while in the MCF-7 cells, exposure to DES or BPA led to three- and two-fold increases in EZH2 expression, respectively, the researchers found. Both the mice and cell lines also had increased EZH2 function as measured by increased mammary histone H3 trimethylation.
"This study also 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," the authors write.