Linking prostate cancer to a widespread industrial compound, scientists have found that exposure to a chemical that leaks from plastic causes genetic changes in animals' developing prostate glands that are precursors of the most common form of cancer in males.
The chemical, bisphenol A or BPA, is used in the manufacture of the hard, polycarbonate plastic of baby bottles, microwave cookware and other consumer goods and has been detected in nearly every human body tested.
Scientists and health experts have theorized for more than a decade that chemicals in the environment and consumer products mimic estrogens and may be contributing to male and female reproductive diseases, particularly prostate cancer.
The new study of laboratory rats suggests that prostate cancer, which usually strikes men older than 50, may develop when BPA and other estrogen-like, man-made chemicals pass through a pregnant woman's womb and alter the genes of a growing prostate in the fetus. One of every six men develops prostate cancer, a rate that has increased during the past 30 years.
Researchers at the University of Illinois at Chicago and the University of Cincinnati exposed newborn rats to low doses of BPA and found the structure of genes in their prostate cells was permanently altered, a process of reprogramming in early life that promotes cancer in adulthood. One key gene was switched on, producing too much of a cell-damaging enzyme that has been detected in cancerous prostate cells but not normal cells.
Also, as the rats aged, they were more likely than unexposed animals to develop precancerous lesions, or cellular damage, in the prostate that have been known for years to lead to prostate cancer in humans.
"The present findings provide the first evidence of a direct link between developmental low-dose bisphenol A ... and carcinogenesis of the prostate gland," the research team, led by Drs. Gail Prins, associate professor of andrology at University of Illinois, and Shuk-Mei Ho, chair of environmental health at University of Cincinnati, reported yesterday in the journal Cancer Research. Exposure to the chemical "may provide a fetal basis for this adult disease" in humans, their report said.
Such findings could have major implications for human disease, and could, at least in part, explain why the prostate cancer rate has surged.
Steve Hentges, a representative of the American Plastics Council, representing the plastics industry, called it "fascinating research, a good piece of research" leading to a new theory that should be further studied.
Marla Cone writes for the Los Angeles Times.