KLK3 and posterior cortical atrophy: For the diagnosis of PCa, the criterion for biomarker of PSA as following: the value of tPSA above 10 ng/ml is evaluated as the positive, indicating high risk of PCa; the value of tPSA below 4 ng/ml is regarded as the negative and low possibility; the value in the range of 4 ng/ml to 10 ng/ml is so-called "grey zone" and the fPSA/tPSA ratio is clinically critical for the precise diagnosis of PCa.