Many studies suggest free PSA as a late-stage predictor of PCa [103] and in particular the percentage of free PSA seems to be inversely associated with risk of finding PCa in biopsy [104]; the researchers show that percentage of free PSA is significantly low in aggressive disease conditions like Gleason score ≥ 7, metastases or positive surgical margins [105]. Here, KLK3 is linked to posterior cortical atrophy.