By significance assay, the AUC of miR-181a-5p exhibited an equal level to that of PSA (p = 0.7962 using cel-miR-40-3p as an exogenous control, p = 0.3133 using cel-miR-54-3p as an exogenous control), indicating that miR-181a-5p can play a similar role to PSA in diagnosis of aggressive prostate cancer. The gene discussed is KLK3; the disease is prostate cancer.