Genes Play Part in Prostate Cancer Among Races
THURSDAY May 15, 2008 -- Genetic differences may explain why white men have a higher prostate cancer risk than Hispanic men, information which may help doctors identify men who are more likely to develop the disease, U.S. researchers say.
They collected blood samples from 932 white men and 414 Hispanic men from south Texas and looked for mutations from the nuclear vitamin D receptor (CDX2 and FokI), which modulates the actions of vitamin D, and from 5-reductase type II (V89L & A49T), which converts testosterone to dihydrotestosterone, a more potent form of the male hormone.
Among non-Hispanic white men with V89L, FokI was associated with a more than a 50 percent increased risk of prostate cancer. This effect was not seen in Hispanic men. Among Hispanic white men, a combination of CDX2 and V89L was associated with a more than threefold increased risk of prostate cancer. This link was not seen in white men.
The findings, published in the May 15 issue of Clinical Cancer Research, provide new information about genetic risks and racial differences, but need to be confirmed in larger studies.
"Prostate cancer is not likely caused by a few genes, but by multiple genes from different pathways. This study illustrates the importance of examining multiple genes to understand genetic risks for prostate cancer and differences seen by ethnicity," study author Kathleen Torkko, an instructor in the department of pathology at the University of Colorado, Denver, said in a prepared statement.
"Going forward, we need not only a better understanding of genetics but a better understanding of race and ethnicity. Studying disease by race is a complex issue, and the public needs to understand that we are trying to raise biological, rather than social, questions," Torkko said.
She said the goal of this research is to find ways to improve management and treatment of prostate cancer. Currently, the most common method for assessing prostate cancer risk is the prostate specific antigen (PSA) test. But the test can identify tumors that may not be a threat, while missing other tumors.
"Men typically have this test after they turn 50 years old, and it can spot a tumor that may not cause a problem in a man's lifetime if left untreated. It could be more likely that a man will die from heart disease or some other ailment before his prostate cancer would kill him," Torkko said.
"At this point, it is not possible to accurately tell which tumors will be the more aggressive ones with our current screening tests. This means that we may be screening and treating some men unnecessarily," she noted.
The National Cancer Institute has more about prostate cancer screening.
Posted: May 2008
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