Objective To investigate the diagnostic value of lipocalin 2 (LCN2) combined with prostate-specific antigen (PSA) in prostate cancer (PCa).Methods Enzyme-linked immunosorbent assay (ELISA) was used to determine the levels of serum LCN2 in patients with PCa (PCa group,n =82),patients with benign prostatic hyperplasia (BPH group,n =40) and healthy subjects (NC group,n =30).The levels of serum PSA were measured by chemiluminescence.The diagnostic value of LCN2 combined with PSA in PCa was analyzed by the receiver operating characteristic (ROC) curve.The relationship between the level of LCN2 and clinical parameters in PCa patients was analyzed.Results The levels of serum LCN2 in PCa group,BPH group and NC group were (88.97 ±40.83) pg/ml,(53.12 ±25.66) pg/ml,(13.34 ±4.86) pg/ml (F=61.306,P ＜0.001).The level of LCN2 in PCa group was significantly higher than that in BPH group and NC group (both P＜0.001).The levels of serum PSA in PCa group,BPH group and NC group were (17.65 ± 8.43) ng/ml,(11.27 ±3.56) ng/ml,(2.61 ±0.87) ng/ml (F=60.959,P＜0.001).The level of serum PSA in PCa group was significantly higher than that in BPH group and NC group (both P ＜0.001).There was positive correlation between serum LCN2 and PSA levels (r =0.360,P ＜ 0.001).The levels of serum LCN2 in PCa patients with different Gleason score,TNM stage and distant metastasis were significantly different (F =8.546,P ＜ 0.001;t =3.421,P =0.001;t =3.622,P =0.010).The area under the curve (AUC) of serum LCN2 was 0.763 (95％ CI:0.677-0.850,P ＜0.001).The sensitivity and specificity of serum LCN2 were 62.2％ and 85.0％.The AUC of PSA was 0.750 (95％ CI:0.665-0.836,P ＜ 0.001).The sensitivity and specificity of serum PSA were 51.2％ and 87.5％.The AUC of LCN2 combined with PSA was 0.822 (95％ CI:0.749-0.895,P ＜0.001).Conclusion Serum LCN2 level in the patients with PCa is significantly higher,which participates in tumor invasion.LCN2 may be a potential serum marker for the diagnosis of PCa.Combined detection of LCN2 and PSA contributes to the early diagnosis of PCa.