A recent study revealed protein biomarker combinations in urine that are unique to prostate cancer and 2 of its stages. A team from the University Health Network in Toronto Canada analyzed urine samples from 50 patients with prostate cancer — 37 with prostate-confined tumors and 13 with tumors that spread — and 24 healthy controls. A targeted protein screen revealed 34 potentially useful biomarkers. Twenty-four of these showed differences between patients with cancer and healthy controls, suggesting these markers could be useful for diagnosis. Fourteen were different between those with prostate-confined tumors and those with tumors that spread, suggesting these markers may be useful for predicting prognosis, or the cancer’s aggressiveness. The team next analyzed urine samples collected from a second, independent group of 117 healthy controls and 90 patients with prostate cancer (61 with stage T2, prostate-confined cancer and 29 with stage T3, cancer that’s spread to nearby tissues called seminal vesicles). The team found a combination of protein biomarkers that predicted the diagnosis correctly in 70% of cases and the stage with 69% accuracy. These “biomarker signatures” outperformed the predictive accuracy of the prostate-specific antigen (PSA) protein, which is currently used for making early diagnoses of prostate cancer. The next step will be further studies with urine samples from 1,000 international patients to validate if the biomarkers identified have broader clinical utilities in prostate cancer. For more details, see the article recently published in National Institutes of Health (NIH) Research Matters.