Photo: Kathryn Marchetti

Exposure before birth to a common chemical used in the manufacture of plastic food and drink containers may cause a predisposition to prostate cancer later in life, a UIC researcher has found.

The chemical compound bisphenol A (BPA), used to make polycarbonate plastic, is one of several chemicals similar to the human hormone estrogen. It has been found in human blood, especially in placental and fetal tissues.

With more than 1.6 million pounds produced in the United States each year, BPA is one of many such chemicals raising concerns among health and environmental experts.

A research team led by Gail Prins, professor of physiology and director of the andrology lab in the department of urology, with University of Cincinnati environmental health scientist Shuk-Mei Ho, found the first evidence linking exposure to low doses of these environmental estrogens during development of the prostate gland in the male fetus to a predisposition in adult men to prostate cancer, which usually develops after age 40.

The team also outlined the mechanisms by which this occurs in an animal model, with findings that could lead to new tests for identifying men at higher risk for prostate disease.

The researchers exposed rats to either low doses of estradiol, a natural estrogen, or to BPA during the developmental period corresponding to the second and third trimester of human pregnancy.

They found that this early exposure predisposed male rats to precancerous lesions of the prostate in old age.

“Most remarkably, early BPA exposure sensitized the prostate to precancerous lesions brought on by exposure of the adult animal to elevated estradiol,” said Prins, senior author of the study published in the June 1 issue of Cancer Research.

“This is highly relevant to people, because relative estradiol levels increase in aging men as a result of their increased body fat and declining testosterone levels.”

The researchers concluded that exposure to estrogens changes the pattern of gene expression in the prostate as the fetus develops. They found that one of these altered genes, which normally shuts down in adulthood, continued at high levels. Similar high levels have been found in prostate cancer cells but not in normal cells.

Because these elevated levels can be measured before prostate cancer develops, this could lead to a method of identifying men at higher risk for the disease, Prins said.

Prostate cancer, which affects 1 in 6 men, is the most common non-skin cancer in the U.S., according to the Prostate Cancer Foundation.

Wan-Yee Tang, of the University of Cincinnati, and Jessica Belmonte de Frausto of UIC also contributed to the study, which was funded by grants from the National Institutes of Health and the Department of Defense.