EurekAlert -- Prostate specific antigen (PSA) levels typically have correlated with prostate biopsy results in the detection of prostate cancer, but that correlation no longer exists for men with a normal prostate exam, according to a new study published in the April 15, 2008 issue of CANCER, a peer-reviewed journal of the American Cancer Society. The study suggests that improved biopsy techniques make PSA less useful in prostate cancer screening.