Commonly Used Chemical Linked to Breast Cancer

In a recent breast cancer study, researchers found evidence linking bisphenol A (BPA) and diethylstilbestrol (DES) to an increased risk of breast cancer among women. While DES is has not been in use in the U.S. since 1971, about four million people are expected to have been exposed to it in utero prior to its discontinuance, and they may be suffering adverse effects from it. On the other hand, BPA has not yet been banned.

The study was published in the May 2014 issue of the Journal of Steroid Biochemistry and Molecular Biology by scientists from the University of Texas at Arlington. They evaluated how these substances interact with long, non-coding RNA, also known as RNA HOTAIR. This molecule is a component of DNA in humans and other vertebrates.

BPA changes RNA HOTAIR expression

Researchers have long that those with high levels of HOTAIR expression are at an increased risk of breast cancer tumors, in addition to pancreatic and colorectal cancers, among others. When HOTAIR is expressed, it interferes with the proper functioning of the genes that inhibit the growth of tumors and can even induce cancer cell death. Through the use of estrogen receptors and estrogen receptor-coregulators, estrogen is primarily responsible for turning HOTAIR expression on or off.

The researchers from the University at Texas found that when a person is exposed to high levels of BPA, the estrogen receptors and estrogen receptor-coregulators are inhibited and function improperly. BPA is a known endocrine disruptor that can lead to high levels of HOTAIR expression and possibly increase the risk of tumor development. Furthermore, when breast tumors are already extant, these cancerous tissues can interact with BPA in a way that increases the likelihood of the growth of additional cancerous tissues.

“We can’t immediately say BPA causes cancer growth, but it could well contribute because it is disrupting the genes that defend against that growth,” said Subhrangsu Mandal, a corresponding author on the breast cancer study. Mandel went on to note that a deeper understanding of the interactions of these molecules could lead to new treatment development in the future.

BPA still used in common household items

In recent years, as the health risks of BPA become clearer, there has been a growing backlash against the use of BPA by manufacturers of common household items. This chemical is primarily used in the production of epoxy resins and polycarbonate plastics. Epoxy resins are used to coat metal items, such as bottle tops, water pipes, and food cans. They are even used in dental sealants and dental composite material. Polycarbonate plastics are also highly prevalent in everyday life, found in everything from compact discs (CDs) to medical devices. BPA is even present in infant bottles, water bottles, polycarbonate tableware, and food storage containers.

According to the National Institute of Environmental Health Sciences, it is possible to be exposed to BPA through water, air, and dust. However, the primary avenues of exposure are from diet. BPA leaches into foods and beverages. When a breastfeeding mother is exposed to BPA, that chemical can even pass into the breast milk and increase the infant’s risk of breast cancer later in life.
The breast cancer study from the University of Texas at Arlington is one more nail in the coffin for BPA. Other studies have also linked this hazardous chemical to adverse health effects, including a study that found BPA may interfere with proper brain development in fetuses and infants.