Among patients who have a prostate biopsy that is negative for cancer, an epigenetic assay may identify those who do not require repeat biopsy, according to research published in The Journal of Urology.

Alan W. Partin, M.D., Ph.D., of The Johns Hopkins University School of Medicine in Baltimore, and colleagues evaluated archived, cancer-negative prostate biopsy core tissue samples from 350 subjects who underwent repeat biopsy within 24 months.

Repeat biopsies with a negative result were controls and those with a positive result were cases. Biopsies were epigenetically profiled for GSTP1, APC, and RASSF1 relative to the ACTB reference gene using quantitative methylation specific polymerase chain reaction. Results were used to confirm the negative predictive value of the epigenetic assay.

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The researchers found that the epigenetic assay had a negative predictive value of 88 percent (95 percent confidence interval, 85 to 91). After adjustment for multiple variables, including age, prostate specific antigen, digital rectal examination, first biopsy histopathological characteristics, and race, the epigenetic assay was found to be the most significant independent predictor of patient outcome (odds ratio, 2.69; 95 percent confidence interval, 1.60 to 4.51).

“Due to its 88 percent negative predictive value, adding this epigenetic assay to other known risk factors may help decrease unnecessary repeat prostate biopsies,” the authors write.

Several authors disclosed financial ties to the biomedical industry.