Researchers from the California Pacific Medical Center in San Francisco have discovered another reason to be wary of products that contain bisphenol A (BPA): It can interfere with the effectiveness of drugs used to fight breast cancer (Carcinogenesis, September 1, 2011).
The study is part of growing research looking at the negative health effects of BPA, a synthetic chemical with estrogenic properties that is used in various products, including dental sealants. In animal studies, exposure to BPA early in life has been shown to prompt hormonal and reproductive issues, including abnormalities in the early development of the brain, prostate gland, and breast tissues.
In this study, the researchers took normal breast cells from high-risk patients, grew them in a laboratory, and found that the cells started acting like cancer cells after they were exposed to BPA and another manmade chemical, methylparaben.
The drug tamoxifen, which is designed to prevent or treat cancer, slows the growth of both healthy and cancerous breast cells, leading to their death. But when tamoxifen was introduced in the experiment, the cells exposed to the two chemicals continued to grow and didn't die, the researchers stated in a story in the San Francisco Chronicle.
Since most breast cancers are driven by the hormone estrogen, the majority of breast cancer drugs are designed to knock down estrogen. BPA and methylparaben mimic estrogen's ability to drive cancer and also seem to be even better than estrogen in bypassing the ability of drugs to treat it, the researchers said.
