Under this background, magnetic resonance imaging (MRI), blood-based biomarkers (Prostate Health Index and the four-kallikrein score), urine-based biomarkers (PCA-3), positron emission tomography imaging using radiopharmaceuticals, and a few risk calculators (SelectMDx and the Stockholm-3 model) have been introduced to improve the accuracy of serum PSA levels in detecting clinically significant cancers before prostate biopsy5,6. Here, KLK3 is linked to cancer.