Because of the lack of reliable imaging tools other than magnetic resonance imaging (MRI), the current standard diagnostic approaches for PCa are the detection of abnormal PSA findings, potentially resulting in digital rectal examination (DRE) to palpate the prostate in order to measure its texture, its stiffness, its enlargement, and the nontargeted transrectal ultrasound (TRUS)-guided biopsy sampling of 10–12 biopsy cores for histopathological diagnosis, which heavily suffers from under sampling and complications. The gene discussed is KLK3; the disease is posterior cortical atrophy.