Study: BPA Can Activate Breast Cancer Cells

A study from Duke University researchers offers new evidence of BPA’s dangers

By Stephanie Soucheray

It’s everywhere, lining metal cans, in sippy cups, on receipts from the store: It’s BPA, a chemical used to make plastics and epoxy resins.

BPA has been in the news the last two years as the Food and Drug Administration has weighed the pros and cons of banning it in food containers. The chemical has been widely banned throughout the European Union and is currently banned from baby bottles in the United States. A known endocrine disruptor, BPA has been shown to mimic estrogen in the body.

Unlike other breast cancers, inflammatory breast cancer may not cause a lump in the breast. Instead, it may cause the breast to be swollen, red, and warm. — Unlike other breast cancers, inflammatory breast cancer may not cause a lump in the breast. Instead, it may cause the breast to be swollen, red and warm. Image courtesy MyHealth, Alberta, Canada

Now, more bad news about BPA: Duke researchers shared new evidence this week that Bisphenol A, or BPA, not only accelerates cell growth in breast cancer but also makes disease treatment less effective.

“We hope to alert clinicians that this is a potential risk factor,” said Scott Sauer. Sauer‘s work was presented as an abstract at the annual joint meeting of the International Society of Endocrinology and the Endocrine Society in Chicago this week. “Doctors should look to see if women with breast cancer have high circulating BPA.”

In 2011, about 160 women per 100,000 in North Carolina were diagnosed with breast cancer. Five percent of those women were diagnosed with inflammatory breast cancer.

Though rare, inflammatory breast cancer is hard to treat because it’s often detected at an already advanced stage and can be hormone receptor negative – meaning traditional hormone inhibitors, like tamoxifen, don’t work to block the growth of cancerous cells. One drug, lapatinib, is often used successfully to treat the cancer if it is HER2-positive.

HER2 is the human epidermal growth factor receptor, and is found in inflammatory breast cancer, or IBC.

Sauer and his colleagues wanted to see which commonly circulating chemicals were most active in cancer cells. In the study, they screened markers in breast cancer cells for a panel of compounds found in plastics, fertilizers and pesticides.

BPA was clearly the most active in IBC cells.

Though many plastic manufacturers now advertise BPA-free products, the chemical is not widely banned in the United States. Image credit: Wikimedia creative commons

Sauer’s work showed that BPA, the chemical commonly found in plastic and food-container linings, stimulated the aggressive cell line that causes IBC. What’s worse, even at normal blood levels BPA blocked the efficacy of cancer drugs used to fight IBC.

“I think this is going to be an interesting area of study because targeted therapies are popular because they shouldn’t have off-target effects,” Sauer said. “But when you rely on only one mechanism for treatment, anything in the environment can throw it off course.”

“These results are certainly consistent with a long line of prior studies showing that BPA can enhance proliferation in breast cancer cells,” said Heather Patisaul, a professor and researcher at North Carolina State University. “What’s striking about this study is the potential mechanism of action. Although BPA has primarily been considered a chemical that interferes with estrogen, this work emphasizes that it may also act via other means.”

Sauer said the work offers a new opening for the FDA to understand just how disruptive BPA can be in adults.

“We’re hoping this will add to a body of evidence,” he said. “The FDA has said, ‘Yes, BPA in fetal development is not good, but we’re not prepared to make a comment on how it effects adults.’ Now we can show it increases cancer and affects treatment.”