One woman I know threw out her canned goods. Another questioned whether her daughter’s death was related to the diet sodas she drank from plastic bottles. Both were among the many members of online support groups I belong to responding to a study from the Duke University School of Medicine and the Duke Cancer Institute. Lead author Gayathri Devi, Ph.D., and colleagues report that they have found that bisphenol A (BPA), a substance common in plastics and food can linings, not only appears to spur inflammatory breast cancer (IBC) cell growth, but also to inhibit the effectiveness of certain treatments.
Dr. Devi and colleagues also reported on a BPA connection to inflammatory breast cancer in a study in 2014. This more recent study looked specifically at how BPA affects IBC cells. BPA is known to disrupt the endocrine system, so it makes sense to suspect that it might be related to breast cancer because the majority of breast cancers are estrogen receptor positive and therefore sensitive to any changes in estrogen levels. However, when this new research looked at how BPA promoted IBC cell growth, the scientists found it has nothing to do with estrogen.
BPA affects the signals that tell cells to divide
Cells know when to divide through a complicated pathway of signals. Among these are epidermal growth factor receptors (EGFR). The EGFR signals other parts of the cell which leads to cell division. In Dr. Devi’s research, low doses of BPA doubled the EGFR signals, which led to increased division of the IBC cells. Some of the drugs that are currently used to treat breast cancer work by interfering with EGFR signaling, but the BPA exposure reduced those drugs’ effectiveness.
This information is important for people whose breast cancers are not estrogen receptor positive because it offers the potential for more effective treatments for them. It is also good news for IBC patients because it suggests why certain forms of treatment may not be as effective for them as for other breast cancer patients. In the past, little IBC specific research has been done, even though it is the most aggressive form of breast cancer.
BPA outside the laboratory
It is important to keep this kind of science news in perspective. The study was done on cells in a laboratory, not on people. All too often a promising insight into cancer found in a lab doesn’t translate into real life solutions. But BPA keeps on turning up as problematic in research.
The National Health Institute of Environmental Sciences website page on BPA says, “The Bisphenol A can leach into food from the protective internal epoxy resin coatings of canned foods and from consumer products such as polycarbonate tableware, food storage containers, water bottles, and baby bottles. The degree to which BPA leaches from polycarbonate bottles into liquid may depend more on the temperature of the liquid or bottle, than the age of the container.”
What should you do?
BPA seems to be everywhere! How much could a little bit hurt you? That answer isn’t clear, but reducing your exposure seems to be a sensible precaution, especially for families with young children and for people already at a high risk for breast cancer.
- When possible, look for containers that are BPA free. Manufacturers often label their containers as BPA free now because they are aware that consumers want to avoid BPA. Plastics with a 3 or 7 recycle code are more likely to be made of BPA. Cans are of particular concern because they often have a resin lining that contains BPA. Some companies have stopped using resin in cans, so read labels.
- Don’t heat plastics. Whether it is in a microwave or dishwasher, heat can release the BPA, and it may leach into your food. Even if a plastic is labeled BPA-free, it is a good practice not to heat other plastics because some of them are also suspect for potential health concerns.
- Don’t panic. The Food and Drug Administration (FDA) considers the low levels of BPA exposure from food containers to be safe. The absence of large-scale studies documenting damage from BPA in humans leads the FDA to conclude that BPA is safe because so little is actually ingested from a container. If you have been using a plastic sandwich container in your lunch box, the BPA in it isn’t likely to get into your body unless you put it in the microwave.
- Do your research. In an article in Science, Warren Cornwall points out that the controversy over BPA’s safety depends in part on what type of study is performed. Some of the studies that the FDA relied on to decide that BPA is safe were funded by the plastics industry. When making decisions about product safety, the FDA tends to avoid studies that look at how a substance affects mice and concentrates on studies in humans. As a consumer, you can decide for yourself how you evaluate laboratory studies on cells or mice and make up your own mind. Don’t decide based on headlines. Look at the evidence carefully when making decisions that affect you and your family.
For IBC patients, the good news is that particular attention is being paid to how IBC cells grow and what treatments might work best for them. We hope that this research will eventually lead to new medicine, but for now reducing BPA exposure might be a good idea.
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