Study finds markers for prostate cancer
Scientists have taken the first major step toward developing a test that can predict who is likely to get prostate cancer, according to a study released Wednesday.
An international research team identified a panel of five genetic markers that greatly increases the risk of prostate cancer in Swedish men, the team announced in the online edition of the New England Journal of Medicine.
Men with at least four of the markers were 4.5 times more likely to develop prostate cancer than men with no markers. Those who had all five markers plus a family history of the disease were 9.5 times more likely to get it.
Other researchers have identified genetic markers that are associated with increased odds of prostate cancer, but the contribution of any individual marker is modest, said Dr. Veda Giri, director of the prostate cancer risk assessment program at Fox Chase Cancer Center, who was not involved in the research.
“Here we see much higher odds ratios, and that’s exciting,” she said.
“It raises the hope that there can be genetic testing for prostate cancer risk.”
The findings need to be validated in other populations; research is already under way in African-American men, who are especially susceptible to prostate cancer. But one of the lead researchers said the team was optimistic the approach would work.
“I think there will be a test fairly rapidly,” said William Isaacs of Johns Hopkins University. “There’s a lot of interest in this, and the technology is not a barrier.
“It will require some additional studies to understand how to use this predictive information most beneficially in the diagnosis and management of prostate cancer, but those could be done relatively quickly. We’re not talking about a five-year program.”
Researchers have long been seeking a genetic basis for prostate cancer, which affects nearly 220,000 U.S. men a year. The fact that multiple genetic alterations appear to be associated with the disease suggests there is no simple genetic mechanism causing it.
“It’s not one gene, one disease,” Giri said. “When they factored in family history, it significantly increased the risk. That highlights that there are probably other genetic events that still need to be elucidated.”
Overdiagnosis, or the detection of tumors that will never become dangerous, is an issue in prostate cancer, especially since the advent of screening tests for PSA (prostate-specific antigen). Scientists know from autopsy studies that a large proportion of men have prostate cancer that did not bother them while they were alive. A test that found more cases of such “pseudo-disease” would not be very useful.