Bisphenol-A and Breast Cancer
This is a rather alarming very early study (meaning, it used mouse models--never is clear how much that will end up translating to humans) about the impact of exposure to Bisphenol-A during pregnancy on female offspring. It suggests that exposure to BPA increases the risk of eventual development of breast cancer. Note that the study does not indicate, even in mice, that the exposure causes breast cancer, "only" that it increases risk.
Here is the introduction and then a link to a MedScape review and interview:
From Medscape Family Medicine Bisphenol-A and Breast Cancer -- It's Beginning to Look a Lot Like DES
An Expert Interview With Hugh S. Taylor, MD
As part of a special feature on the potential risks from exposure to bisphenol-A (BPA) during pregnancy, Medscape talked to Hugh S. Taylor, MD. He is Professor of Obstetrics, Gynecology, and Reproductive Sciences, Professor of Molecular, Cellular, and Developmental Biology and Chief of Reproductive endocrinology and Infertility at the Yale School of Medicine. He is also Director, Yale Center for Endometrium and Endometriosis. He was the lead investigator on a study that identified an important mechanism triggered by BPA exposure during pregnancy that could lead to breast cancer decades later in the offspring.
Medscape: Could you describe your study on the risk of breast cancer in female offspring of mother's exposed to bisphenol-A (BPA), and just give any thoughts on whether this was clinically significant?
Dr. Taylor: In this study we used a mouse model to look at the risk of breast cancer or -- more precisely -- the mechanism by which breast cancer risk may be increased after in utero exposure to either diethylstilbestrol (DES) or BPA. We looked at mothers ingesting either of these estrogen-like compounds during pregnancy and then determined what effect these compounds had on the female offspring after they had been born and as adults. They weren't being exposed to these agents as adults. They were only exposed in utero as fetuses.
In this study, we looked at the breast tissue. Recent evidence demonstrates that women who were exposed to DES as fetuses start to show an increased relative risk of breast cancer when they reach ages greater than 40. This drug was used in the 1950s and 1960s to prevent miscarriage in high-risk women, and now we are seeing an increased risk of breast cancer in their daughters, who are getting to the age where breast cancer risk starts to climb. We wanted to getat the mechanism behind that risk. How could exposure to estrogen as a fetus be influencing your risk of breast cancer half a century later as a 40-, 50-, 60-year-old adult?
We also wanted to determine if BPA had the same effect. While the data on BPA in humans is less clear than with DES, adult animal models are clearly showing that in utero exposure to BPA can increase the risk of pre-neoplastic changes in the breast and the risk of developing breast cancer when other carcinogens are also administered. In these adult animal models, BPA increases their susceptibility or risk rather than directly causing increased breast cancers.