KLK3 and cancer: There were significant differences in PSA level (p = 0.014), PSA density (PSAD) (p = 0.002), PHID (p < 0.001), cancer core number at prostate biopsy (p = 0.001), cancer positive core rate (p < 0.001), PCa detection rate (p < 0.001), csPCa detection rate (p < 0.001), distribution of ISUP GG at biopsy (p < 0.001), and distribution of ISUP GG (p < 0.001) at RP among groups if classified by PHI level range (0–26.9/27.0–35.9/36.0–54.9/ ≥ 55.0).