Among all individual analyses, the PSAD showed good sensitivity of 81.13% and specificity of 80% with a cutoff >0.188843 for diagnostic discrimination in PCa (AUC = 0.8294, 95% CI: 0.85–0.91, p < 0.0001), while the prostate volume (AUC = 0.777, 95% CI: 0.85–0.91, p < 0.0001) and f/t PSA (AUC = 0.728, 95% CI: 0.85–0.91, p < 0.001) showed fair predictive ability for PCa as well (Table 3, Figure 2). The gene discussed is KLK3; the disease is posterior cortical atrophy.