Patients with PC showing high levels of prostate-specific antigen and high Gleason scores were associated with a high risk of viral infection (ORs 1.1, 95% CI 1.000–1.003; p = 0.045 and ORs 6.18, 95% CI 1.26–30.33, p = 0.025, respectively). The gene discussed is KLK3; the disease is viral infectious disease.