KLK3 and prostate cancer: The cut-off point of 4.0 ng/mL was considered for PSA screening and studies have shown that with this threshold the negative predictive value of PSA for detecting prostate cancer is 89% in men with a median age of 69 years [33], so patients with PSA levels >4 ng/mL in two tests should undergo other work-up like prostate biopsy, multiparametric MRI [34] and whole body bone scans [35].