Brominated flame retardants (BFRs) are present in a wide variety of household fixtures and furniture, and particles of this may increase the risk of breast cancer through prolonged exposure at critical times in a woman’s life.
BFRs are endocrine disruptors, and since they are not tightly bound to the substances they are included into, they are able to escape into the household environment. Endocrine disruptors can be problematic to protect against since they can exert harmful effects even at low doses. Exposure to endocrine disruptors is most disruptive in the foetal stage and during infancy; these compounds also easily cross the placental boundary and are found in breast milk. At high exposures, cells have a toxic response, but at a low dose, similar to the levels of naturally occurring hormones, endocrine dysregulation is the outcome.
Exposure to these compounds can cause problems for organs such as mammary glands, which are sensitive to hormones, which BFRs can mimic. “BFRs pose a significant risk, particularly during sensitive periods, from intrauterine life to puberty and during pregnancy,” said Professor Plante, co-director of the Intersectoral Centre for Endocrine Disruptor Analysis and environmental toxicologist.
The researchers exposed female rodents to a mixture of BFRs, similar to that found in house dust, prior to mating, during gestation and during lactation. Biologists were able to observe the effects on the offspring at two stages of development and on the mothers.
Early development of mammary glands was seen in prepubertal rats. For pubescent rats, the results, published in 2019, showed a deregulation of intercellular communication. Similar effects were observed in female genitors in a 2017 study. All of these effects are associated with an increased risk of breast cancer.
In the early 2000s, observation showed that human exposure to BFRs peaked, Professor Isabelle Plante pointed out. “Young women exposed to BFRs in utero and through breastfeeding are now in the early stages of fertility. Their mothers are in their fifties, a period of increased risk for breast cancer,” said Prof Plante. This is why the team is currently studying endocrine disruptors related to a predisposition to breast cancer, funded by the Breast Cancer Foundation and the Cancer Research Society.
In all three studies, most of the effects were observed at a low dose, raising questions about the current legislation for endocrine disruptors. “To evaluate the ‘safe’ dose, experts give an increasing dose and then, when they observe an effect, identify it as the maximum dose. With endocrine disruptors, the long-term consequences would be caused by lower doses,” reported Prof Plante.
Source: Medical Xpress
Journal information: Rita-Josiane Gouesse et al, In Utero and Lactational Exposure to an Environmentally Relevant Mixture of Brominated Flame Retardants Induces a Premature Development of the Mammary Glands, Toxicological Sciences (2020). DOI: 10.1093/toxsci/kfaa176
