A. Karim Kader, M.D., Ph.D., from the Wake Forest University School of Medicine in Winston-Salem, N.C., and colleagues analyzed data from 1,654 men who were part of a prostate cancer clinical trial. All of the men initially had a negative biopsy and then underwent additional biopsies after two and four years. They also underwent prostate-specific antigen testing and received a genetic score based on testing of a panel of 33 single nucleotide polymorphisms that had been previously associated with prostate cancer.

The researchers found that, even after adjusting for various clinical factors and family history, the genetic score was a significant predictor of a subsequent positive biopsy. The area under the receiver operating characteristic curve (AUC) was higher for the genetic score (0.59) than for any other predictor of prostate cancer; the AUC improved from 0.62 to 0.66 when the genetic score was added to the best clinical model. Use of the genetic score reclassified prostate cancer risk in 33 percent of men and reduced the number of biopsies needed to detect prostate cancer. The genetic score was most useful in classifying risk for men at intermediate risk.

"Adding genetic markers to current clinical parameters may improve prostate cancer risk prediction. The improvement is modest but may be helpful for better determining the need for repeat prostate biopsy," Kader and colleagues conclude. "The clinical impact of these results requires further study."

Several authors disclosed financial ties, including employment, to GlaxoSmithKline. Several authors have filed a patent application related to the technology used in the study.

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