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 hard, polycarbonate plastic for baby bottles, microwave cookware and other consumer goods, and it has been detected in nearly every human body tested.
For The Record
Los Angeles Times Friday June 02, 2006 Home Edition Main News Part A Page 2 National Desk 1 inches; 57 words Type of Material: Correction
Prostate cancer: An article in Thursday's Section A about a study that linked prostate cancer to a widespread industrial compound said that rats "were injected with doses 100 to 1,000 times higher than the most recent human testing done by federal officials in 2004." It should have said the testing was reported by federal officials in 2004.
Scientists and health experts have theorized for more than a decade that chemicals in the environment and in 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 over 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 in every six men develops prostate cancer, a rate that has increased over the last 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," according to the researchers. Results from the team, led by Gail S. Prins, associate professor of andrology at the University of Illinois at Chicago, and Shuk-mei Ho, chair of environmental health at the University of Cincinnati, are reported today in the journal Cancer Research.
Exposure to the chemical "may provide a fetal basis for this adult disease" in humans, the report said.
Dr. Rebecca Sokol, a USC medical school professor who specializes in male hormone research, called the study "cutting-edge." She said it added to a growing body of research, called epigenetics, that suggested environmental chemicals could alter how DNA sequences turned on and off in a fetus, permanently imprinting the genes of a child and sensitizing him or her to disease in adulthood.
