In particular, it is important to discriminate between patients with overall low-risk PCa (GS < 6/ISUP group 1, with PSA < 10 ng/mL and/or T1-T2a) who may benefit from treatment deferral (i.e. active surveillance) and those with intermediate-risk PCa (GS 7, defined as either 3 + 4, ISUP group 2, or 4 + 3, ISUP group 3, and/or T2b) who require active treatment4. The gene discussed is KLK3; the disease is posterior cortical atrophy.