KLK3 and benign prostatic hyperplasia: However, there were significant differences in total prostate-specific antigen (tPSA) (csPCa: 180.85 ± 150.14 ng/mL, BPH: 18.57 ± 15.52 ng/mL, p = 0.001), free/total PSA (f/tPSA) (csPCa: 0.098 ± 0.071, BPH: 0.197 ± 0.101, p < 0.001), PSA density (PSAD) (csPCa: 2.58 ± 2.18, BPH: 0.24 ± 0.17, p = 0.001), and PGV (csPCa: 49.05 ± 44.80 mm3, BPH: 74.37 ± 35.37 mm3, p = 0.039) between csPCa patients and BPH patients with “nodule in nodule.” The areas under the receiver operating characteristic (ROC) curves for tPSA, f/t PSA, PSAD, and PGV were 0.696, 0.835, 0.778, and 0.770, respectively (Fig. 4).