In prostate cancer, the diagnostic performance of PSA alone was already high (ROC AUC: 0.97; 95% CI: 0.94–0.99), and the addition of hPG80 did not further improve the overall diagnostic accuracy (combined ROC AUC: 0.97; 95% CI: 0.94–0.99). The gene discussed is KLK3; the disease is prostate cancer.