Prostate cancer is the second leading cause of cancer-related deaths among men in the United States. According to the National Cancer Institute, 15 percent of U.S. men will be diagnosed with prostate cancer at some point in their lives. A new study published in January 2014 attempts to pinpoint why these numbers are so high and they have come up with this explanation: Early fetal exposure to low levels of bisphenol A (BPA) may make men more susceptible to prostate cancer later in life.
BPA is known to be a gender-bending endocrine disrupter that acts as an estrogen. It is used to make polycarbonate plastics and can be found in aluminum beverage cans, most food cans, infant formula that comes in cans, dental sealants, paper receipts, and epoxy-lined beer cans. An estimated 90+ percent of Americans carry traces of BPA in their bodies, so that there is almost “universal fetal exposure” to BPA.
In searching for a connection between fetal BPA exposure and future prostate cancer, researchers from the University of Illinois at Chicago implanted stem cells from deceased young men into lab mice. Environmental Health News reports:
“When the mice were fed BPA by mouth for the first two weeks of life, 33 percent of the stem cells had cancerous or precancerous lesions later in life. Forty-five percent of the cells that were exposed to BPA before and after mice implantation developed precancerous or cancerous lesions later. In comparison, only 12 percent of the mice not exposed to BPA during development had cancer or precancerous lesions later in life.”
The researchers propose that early exposure to BPA, an estrogenic compound, permanently reprograms a fetus’ stem cells. Those stem cells are then used to replenish organs throughout the course of a person’s life, and if those stem cells are extra-sensitive to estrogen as a result of early exposure, they will pass on that sensitivity to the prostate tissues later in life. It’s already known that men’s rising levels of estrogen, which happens naturally as they age, are partly responsible for causing prostate cancer.
While this study cannot replicate human physiology perfectly, it is still considered to be “some of the strongest and most convincing evidence to date linking early life BPA exposure and cancer,” according to Heather Patisaul from the University of North Carolina. It’s an excellent study because it looks at the effect of stem cells in a whole animal, not just a dish.