KLK3 and posterior cortical atrophy: The predictive ability of PHI to diagnose PCa (AUC = 0.703) exceeded that of serum PSA (AUC = 0.525), free PSA (AUC = 0.615), p2PSA (the primary form in PCa tissue) (AUC = 0.557) or percent-free PSA (AUC = 0.648).