Newly Discovered Prostate Cancer Genetic Variants Could Make Testing For Risk Better
Screening for prostate cancer has seen huge advances, with scientists recently identifying 23 new genetic variants associated with risk of the disease. These discoveries have made them able to explain up to a third of the inherited risk when combined with previous studies, which had identified about 77 common genetic variants. With the new discovery, that number goes up to 100. Altogether, doctors will now be able to spot one percent of men who are up to six times more prone to developing prostate cancer than the average population.
The research, published Sunday in Nature Genetics, was part of a huge international study that included almost 90,000 men of different ethnicities, including European, African, Japanese, and Latino. Researchers found that screening for these 100 variants identified 10 percent of men with a risk almost three times as high as the population average. This number, according to the researchers, was high enough for them to take the next step in determining whether targeted genetic screening can be an effective method of testing for prostate cancer risk. In all, they found that the 10 percent men at highest risk were 2.9 times more likely than the average person to develop prostate cancer, while the top one percent were 5.7 times more likely to develop the disease.
For the research, the scientists examined genetic data from 87,040 men from all over the world. Among the participants were 43,303 men with prostate cancer; the rest were healthy control participants. This study enabled them to identify 16 new genetic markers linked to prostate cancer risk in European men. Of these, one was found to be associated with an increased risk of early-onset disease in European men, and seven were associated with men with mixed heritage.
The study was conducted to improve statistical power and increase scientists' chances of identifying new variants. Researchers can now explain 33 percent of the inherited origins of prostate cancer in European men. To test if these markers can be incorporated with other tests to improve diagnoses, a new clinical trial called BARCODE will soon begin. That project aims to screen 5,000 men for genetic links to prostate cancer. The researchers also hope to widen the scope of genetic testing to detect rare or more dangerous forms of prostate cancer, which aren't detectable with current tests, such as the Prostate-Specific Antigen test.
"Our study tells us more about the effect of the genetic hand that men are dealt on their risk of prostate cancer," lead researcher Professor Ros Eeles said in a statement. "We know that there are a few major genes that are rare and significantly affect prostate cancer risk, but what we are now learning is that there are many other common genetic variants that individually have only a small effect on risk, but collectively can be very important.”
Prostate cancer is among the most common type of cancers. As the fifth leading cause of cancer deaths in the U.S., approximately 209,292 men were diagnosed with it in 2011, while 27,970 men died from it.
Source: Eeles R, et al. Nature Genetics. 2014.