Study shows BPA may pose breast cancer risk

WASHINGTON – A new study of fetal exposure to BPA, a plastic additive found in some food packaging, shows that the chemical altered mammary gland development in monkeys. The researchers reported that the changes they observed in the monkeys reinforce concerns that BPA – bisphenol A – could contribute to breast cancer in women.

The research was published Monday in the Proceedings of the National Academy of Sciences.

For this study, the researchers fed pregnant rhesus macaques a piece of fruit containing BPA every day during their third trimester of pregnancy. The monkeys’ blood levels of BPA reached about the average level that BPA has been observed in human blood in the United States, said Patricia Hunt, a geneticist at Washington State University and one of the study’s authors.

After female offspring of these BPA-exposed monkeys were born, the researchers looked at their mammary glands. They found changes in the glands that give rise to dense tissue – something that in humans is a risk factor for breast cancer, Hunt said.

BPA is used mainly in polycarbonate plastics, such as those used for some kinds of food and drink packaging, and epoxy resins used in some food cans and other products. Scientists say it mainly enters the human body as a result of leaching from the packaging into food and drink.

Previous studies in mice have shown a correlation between changes in the mammary gland as a result of fetal BPA exposure and an increased risk of cancer later, as adults. The chemical industry argued that BPA-exposed mice might not be a good model for understanding the effects on humans, Hunt said. But the new study found the same results in primates, which are more similar to humans.

“This monkey study closes the gap between rodents and humans and suggests that we have much to fear from this chemical,” she said.

The Food and Drug Administration has said that BPA is safe. On March 30, the FDA rejected a petition by the Natural Resources Defense Council to ban it. The FDA then said that more studies were needed.

The American Chemistry Council said the study was faulty and didn’t alter its view that BPA is safe. Other studies have convinced regulators in the U.S., Europe and Japan that BPA isn’t a carcinogenic hazard, said the council’s Steven Hentges.