By significance assay, the AUC of miR-181a-5p exhibited an equal level to that of PSA (p = 0.776 using cel-miR-40-3p as an exogenous control, p = 0.1898 using cel-miR-54-3p as an exogenous control), indicating that miR-181a-5p can play a similar role to PSA in diagnosis of prostate cancer (Figure 3A and Figure S4A). Here, KLK3 is linked to prostate cancer.