March 5, 2014
High Levels Of BPA Linked To Prostate Cancer
Rebekah Eliason for redOrbit.com - Your Universe Online
A new study from the Cincinnati Cancer Center discovered that if the chemical bisphenol A (BPA) is found in men’s urine it may be a marker for prostate cancer. According to the researchers, even low levels of exposure to BPA can cause changes within non-malignant and malignant prostate cells.These findings provide the first evidence that urinary levels of BPA could predict prostate cancer. Also, the researchers discovered evidence suggesting that disruption of the cell duplication cycle from exposure to low amounts of BPA may be responsible for the development of cancer in the prostate.
Used to make hard, clear plastic and found in many common food product containers, BPA is an environmental pollutant and functions in the body similar to estrogen. Previously it has been linked with neurological defects, diabetes and several cancers such as breast and prostate.
Shuk-mei Ho, PhD, director of the Cincinnati Cancer Center, Jacob G. Schmidlapp Chair of Environmental Health and professor at the University of Cincinnati College of Medicine and lead investigator of this study reported that humans are commonly exposed to BPA. Although animal studies have confirmed BPA contributes to prostate cancer development, the data for humans is scarce.
“Prostate cancer is the second most common cancer among men in North America, and one in six men will develop it over their lifetime,” she says. “However, the cancer is rarely diagnosed in men under the age of 40 with almost two-thirds of cases reported in men at age 65. Major contributing factors other than age are race and family history, whereas little is known about the impact of endocrine disruptors on prostate cancer.”
Ho estimated that in the general population of the United States, widespread exposure to BPA exceeds 90 percent. The major types of exposure come from absorption through the skin, inhalation and ingestion form contaminated food and water.
“As an endocrine disruptor that mimics estrogen and thyroid hormones, BPA also acts as a metabolic and immune disruptor,” says Ho. “The adverse health effects of BPA are extensive, and studies in animals have proven this.”
“However, human studies linking BPA exposure to heightened cancer risk are limited,” she continues. “Our study examined the association between urinary BPA levels and prostate cancer and assessed the effects of BPA on the initiation of centrosome abnormalities as an underlying mechanism promoting prostate cancer formation.”
One of the organelles necessary for proper cell division is the centrosome. Abnormalities in these organelles are commonly found in cancers.
For this study, the researchers used urine samples to analyze the PSA levels in 60 urology patients. They found higher levels of BPA in patients with prostate cancer than in non-prostate cancer patients with 5.74 μg/g creatine versus 1.43 μg/g creatine. The difference was discovered to be more extreme when examining patients under the age of 65.
In addition, the researchers examined normal and cancerous prostate cells through immunofluorescence which allowed them to visualize the distribution of BPA and specifically examine centrosomal abnormalities and growth patterns.
“Exposure to low doses of BPA increased the percentage of cells with centrosome amplification two- to eight-fold,” Ho says. “BPA is not a recognized carcinogen, and questions surrounding the mechanism behind the positive correlation of BPA exposure with prostate cancer have arisen.”
“Several studies have shown that centrosome amplification is a major contributing factor to chromosomal mutation in human tumors. We examined the centrosome profile of prostate cancer cells treated with BPA and found that treatment with BPA increased the number of cells with abnormal centrosomes.”
“All of these findings reveal a previously unknown relationship between BPA exposure and prostate cancer and suggest a mechanism underlying the role of BPA in cellular transformation and disease progression. With this insight, we hope to further investigate ways we can decrease exposures to potentially cancerous-causing chemicals in every day products and substances and reduce the onset of prostate cancer in men.”
This study was published in the March 3 edition of the journal PLOS ONE.