KLK3 and prostate cancer: The National Comprehensive Cancer Network (NCCN) prostate cancer guidelines use Gleason grade group (GG) 1 or 2, <50% biopsy cores positive and PSA 10–20 ng/mL as features that define “favorable intermediate-risk” disease and suggest that AS may be an option for some men within this risk category [6], prompting a pressing need to define AS eligibility more precisely within this group.