Study identifies new genetic variations that could point to elevated prostate cancer risk.
New study has identified 63 new genetic variations that could indicate higher risk of prostate cancer in men of European descent. The study is the result of a six-year long research process by Fredrick R. Schumacher, PhD, a cancer epidemiology researcher at Case Western Reserve University School of Medicine, and an international team of more than 100 colleagues. The findings are published in Nature Genetics. The study findings contain significant implications for which men may need to be regularly screened because of higher genetic risk of prostate cancer . The new findings also represent the largest increase in genetic markers for prostate cancer since they were first identified in 2006.
‘Sixty three new genetic variations identified that could indicate higher risk of prostate cancer in men of European descent.’
The changes, known as genetic markers or SNPs ("snips"), occur when a single base in the DNA differs from the usual base at that position. There are four types of bases: adenine (A), thymine (T), guanine (G), and cytosine (C). The order of these bases determines DNA's instructions, or genetic code. They can serve as a flag to physicians that a person may be at higher risk for a certain disease. Previously, about 100 SNPs were associated with increased risk of prostate cancer. There are three billion base pairs in the human genome; of these, 163 have now been associated with prostate cancer. One in seven men will be diagnosed with prostate cancer during their lifetimes.
"Our findings will allow us to identify which men should have early and regular PSA screenings and these findings may eventually inform treatment decisions," said Schumacher. PSA is a blood test used to screen for prostate cancer. It measures the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein produced by both cancerous and noncancerous tissue in the prostate.
Adding the 63 new SNPs to the 100 that are already known allows for the creation of a genetic risk score for prostate cancer. In the new study, the researchers found that men in the top one percent of the genetic risk score had a six-fold risk-increase of prostate cancer compared to men with an average genetic risk score. Those who had the fewest number of these SNPs, or a low genetic risk score, had the lowest likelihood of having prostate cancer.
In a meta-analysis that combined both previous and new research data, Schumacher, with colleagues from Europe and Australia, examined DNA sequences of about 80,000 men with prostate cancer and about 60,000 men who didn't have the disease. They found that men with cancer had a higher frequency of 63 different SNPs (also known as single nucleotide polymorphisms) that men without the disease did not have. Additionally, the more of these SNPs that a man has, the more likely he is to develop prostate cancer.
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Currently, researchers don't know which of the SNPs are the most predictive of increased prostate cancer risk. Schumacher and a number of colleagues are working to rank those most likely to be linked with prostate cancer, especially with aggressive forms of the disease that require surgery, as opposed to slowly developing versions that call for "watchful waiting" and monitoring.
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In addition to the work in the new study, which as noted, targets men of European background, there are parallel efforts underway looking at genetic signals of prostate cancer in men of African American and Asian descent.
Source-Eurekalert