Moffitt researchers study prostate cancer risk in African-American and Caucasian men

April 03, 2006

Tampa, FL – Prostate cancer is the most common cancer in men, comprising approximately one-third of all male-specific cancers. The incidence and mortality rates of prostate cancer among African-American men are significantly higher than that of any other ethnic group in the United States and the world. The exact cause of prostate cancer is unknown but research has shown race, age, family history and steroid hormone levels are risk factors.

In a case-control study with 420 patients with prostate cancer (127 African Americans and 293 Caucasians) and 487 controls (120 African Americans and 367 Caucasians), recruited at the H. Lee Moffitt Cancer Center & Research Institute, the University of Arkansas for Medical Sciences, University Hospital, the Central Arkansas Veterans Healthcare System and the Jefferson Regional Medical Center, the frequency of the UGT polymorphism was compared.

UGT is responsible for removing excess androgens (testosterone is an androgen), which are a potential risk factor for prostate cancer. High levels of testosterone increase risk for prostate cancer. Individuals without the UGT2B17 gene (UGT2B17 is a UGT) may have higher levels of testosterone, and therefore may have higher risk than people with the UGT gene.

Approximately 11 percent of the male population does not have this gene. When researchers genotyped the prostate cancer patients, approximately 20 percent of them did not have the UGT2B17 gene. There is an approximate 90 percent risk increase for prostate cancer in Caucasians without UGT2B17. Therefore, researchers can identify individuals who have high risk for prostate cancer by simple genotyping of the UGT2B17 gene.

“Although one out of six males will develop prostate cancer in their lifetime, we still don’t know exact causes,” says Jong Park Ph.D., assistant professor in Moffitt’s Risk Assessment, Detection and Intervention Program. “Just as some people have blue eyes and some have B negative blood type, some people are naturally more cancer resistant because of their genetic background. In particular, our genetic blueprint (DNA) encoded instruction to make proteins (enzymes) that regulates all body functions. All carcinogens are also metabolized by enzymes. Large differences in the activity of these enzymes are known to exist between individuals. These differences are explained, in part, by inherited differences in the genes (known as polymorphisms) that encode these metabolizing enzymes.”

Researchers found that genetic polymorphism influences the risk of prostate cancer. This information may influence strategies for prevention, early detection and identification of high risk populations for prostate cancer.

Park, the study’s principal investigator, presented the findings April 3 at the American Association for Cancer Research meeting in Washington, D.C. His findings will also appear in the journal Cancer Epidemiology, Biomarkers and Prevention.

In 2001, the National Cancer Institute awarded Moffitt the status of a Comprehensive Cancer Center in recognition of its excellence in research and contributions to clinical trials, prevention and cancer control. Additionally, Moffitt is a member of the National Comprehensive Cancer Network, a prestigious alliance of the country’s leading cancer centers, and is listed in U.S. News & World Report as one of the top cancer hospitals in America. Moffitt’s sole mission is to contribute to the prevention and cure of cancer.