Thus, PSA screening has resulted in an over-diagnosis of PCa, and in many unnecessary biopsies of benign disease; only about 30–40% of the biopsied men are diagnosed with PCa and specifically, in patients with PSA levels of 4 to 10 ng/ml, the detection rate of PCa was merely 20% or less thus defining the region as a “grey zone”. This evidence concerns the gene KLK3 and posterior cortical atrophy.