June 11 (UPI) -- Researchers in Britain have developed a saliva test for prostate cancer, and they plan to start a wider trial soon using spit samples from doctor's offices, to find whether the test should be put into more common use.
Scientists at the Institute of Cancer Research in London are using 150 DNA markers to identify men in the top 10 percent risk group -- 2.7 times greater than the general population -- and the 1 percent with a 5.7 times greater risk.
They compared the DNA of 80,000 prostate cancer patients and 61,000 healthy controls. Their findings were published Monday in the journal Nature Genetics. They identified 63 new genetic variations in the DNA code that increase the risk of prostate cancer.
Prostate cancer is the most common cancer among American men except for non-melanoma skin cancer, according to the Centers for Disease Control and Prevention. And as of 2015 it was the second-leading cause of cancer death in men behind lung cancer.
Current prostate cancer screening methods include digital rectal exams, biopsies and prostate specific antigen, or PSA, tests. But because the cancer grows slowly, they are not always effective. Specifically, PSA tests can give false positives and sometimes miss more aggressive cases
Researchers in Britain reported in March that the standard PSA test had no significant effect on survival rates.
ICResearch scientists say they now can account for almost 30 percent of a man's inherited risk of prostate cancer.
"By looking at the DNA code of tens of thousands of men in more depth than ever before, we have uncovered vital new information about the genetic factors that can predispose someone to prostate cancer, and, crucially, we have shown that information from more than 150 genetic variants can now be combined to provide a readout of a man's inherited risk of prostate cancer," Dr. Ros Eeles, professor of oncogenetics at the ICR, said in a press release.
"If we can tell from testing DNA how likely it is that a man will develop prostate cancer, the next step is to see if we can use that information to help prevent the disease."
Among those with the greatest risk, researchers found the odds of developing prostate cancer were one in two, compared with 1 in 11 in the general population. For the top 10 percent in risk, it was one in four.
Researchers found that most of new genetic variants include genes that are involved in communication between immune cells and others around the body. The researchers theorize that genetic errors in immune pathways may be affecting prostate cancer risk.
And in turn, this can lead to potential future treatment of prostate cancers.
"We have seen dramatic progress in recent years in our understanding of the genetics of prostate cancer, and this new research is another big step forward that tells us more about why some men develop the disease and others don't," Dr. Paul Workman, chief executive of the ICR, said. "We are on the cusp of moving from theory to practice -- from explaining how genetics affects prostate cancer risk, to testing for genetic risk and attempting to prevent the disease."