Common Chemical in Household Products May Increase Breast Cancer Risk

The common chemical bisphenol A (BPA) was found to directly affect the mammary gland in mouse embryos, increasing the risk of developing breast cancer, a recent study suggests.

BPA is found in numerous plastic and resin household products and has been detected in most urine samples that are representative of the US population. BPA has been linked to many adverse health effects in humans and can even cross the placenta in the womb.

“…Exposure in the womb to endocrine disruptors such as BPA may be a main factor responsible for the increased incidence of breast cancer in women,” said the lead study investigator, Lucia Speroni, PhD.

Researchers used a new culture method called ex vivo that involves the examination of the whole mammary gland growth outside the organism.

During the study, mammary buds were extracted from 14-day-old mouse embryos, which is a critical time for the mammary development in rodents.

The mammary buds developed and grew in culture dishes for 5 days, which allowed researchers to examine how the mammary gland develops in real time.

Various BPA doses were tested and then the effects were compared with estrogen. The results of the study showed that there was an increase in growth of the mammary bud from BPA, which were environmentally relevant.

The study revealed that BPA did not have the same effect on the mouse mammary bud as estrogen, which was found to inhibit mammary gland growth.

“We knew from our previous research that BPA causes changes to breast tissue associated with a higher predisposition to breast cancer later in life,” Speroni said. “However, until now, we did not know whether this was a direct effect on the fetus or an indirect effect from the mother's exposure.”

More research will be done to assess why and to find the mechanism that BPA disrupts mammary gland development. Additionally, researchers look to test other hormonally active chemicals that could cause breast cancer.

“We now have a way to test the impact of endocrine-disrupting chemicals on the development of the mouse mammary gland at different doses and obtain results in less than a week,” Speroni said.