KLK3 and cancer: To predict clinically insignificant cancer in patients with clinical T1c (non-palpable) PCa, Epstein et al. reported a set of criteria[9], and later updated to the contemporary version, including PSA density < 0.15 ng/mL, biopsy Gleason score ≤ 6, the presence of tumor in two or fewer cores, and no more than 50% involvement by tumor in any core[10].