Suspicion of the presence of PCa, alerted as a result of an abnormal serum PSA and/or and abnormal DRE, requires an invasive procedure to provide histological confirmation with biopsies (usually >12) almost always obtained via imaging with a transrectal ultrasound (TRUS) probe to ensure spatial positioning of biopsy needles. This evidence concerns the gene KLK3 and posterior cortical atrophy.