DNA test may gauge prostate cancer risk

A simple blood test may determine which men are likely to develop prostate cancer, according to a team of U.S. and Swedish researchers.

They found that five genetic variants previously associated with prostate cancer risk have a strong cumulative effect, and a man with four of the five variants has an increased risk of 400% to 500% compared with men with none of the variants. When a family history of prostate cancer was added to the equation, that risk increased to 900%, reported researchers from Wake Forest University Baptist Medical Center in Winston-Salem, NC, Johns Hopkins Medical Institutions in Baltimore, and the Karolinska Instituet in Stockholm.

“This is significant, and could affect clinical care,” said senior researcher Jianfeng Xu, MD, DrPH, of Wake Forest. “The information could substantially improve physicians’ ability to assess risk and determine the need for more aggressive screening or even a biopsy.”

The test may be especially useful in men with a family history of prostate cancer or those who have a marginally elevated PSA, he said.

Researchers analyzed DNA variants in blood samples drawn from 2,893 men with prostate cancer and 1,781 healthy individuals of similar ages. Individually, the variants were only moderately associated with prostate cancer. Combined, however, and with family predisposition for the disease factored in, they accounted for 46% of cases in the group. Further, the study team found that the cumulative risk associated with the genetic variants and family history is independent of PSA results at diagnosis.

The study will be published in the Feb. 28, 2008 edition of the New England Journal of Medicine.