UroToday – Prostate cancer gene 3 is a promising new prostate cancer (CaP) biomarker as it is over-expressed in CaP tissue compared to normal prostate tissue. As such, Dr. Donna P. Ankerst and colleagues hypothesized that its inclusion in the Prostate Cancer Prevention Trial (PCPT) risk calculator may augment its predictive capabilities. Their research report appears in the October 2008 issue of the Journal of Urology.

Specimens for the analysis were collected from 521 patients at four North American centers – along with data on PCA3, PSA, DRE, age, race, and history of prostate biopsy. In addition, a cohort from Europe comprised of 443 patients at high risk for CaP, was evaluated for external validation of posterior risks.

A noted difference between the 521 men in the PCA3 group and the 5,519 men in the PCPT placebo group used to derive the PCPT risk calculator is that the PCPT cohort was a screened population. Only 11.7% of the PCPT placebo group had undergone a prior biopsy compared to 49.5% of the PCA3 group. Only 21.2% of CaP was high grade in the group of PCPT men, compared to 42.7% in the PCA3 cohort. This demonstrates that the PCA3 cohort was at a much greater risk for CaP and high-grade disease.

A “likelihood ratio” (LR) which expresses how much more likely a given PCA3 value is for cases vs. controls was used. A LR >1 means the PCA3 value is more often seen in cases while an LR