Combining a PSA cut-off of 20.85 ng/mL with an ALP cut-off of 44.0 IU/L yielded a 100% detection rate, while PSA above 20 ng/mL, DRE >T2c, and Gleason score >7 predicted 95% of bone metastasis in this cohort. Here, KLK3 is linked to bone metastasis.