Abstract: Objective To investigate the expression of prostate specific membrane antigen(PSMA) in prostate cancer tissues and peripheral blood,and to analyze the relationship between PSMA and Gleason score and its value in early diagnosis and prognosis.Methods Clinical data of 270 patients with prostate cancer and 50 patients with BPH treated in our hospital from March 2015 to June 2020 were retrospectively analyzed.Immunohistochemical staining(IHC) was used to detect PSMA expression in tissues,and analyze the correlation between PSMA expression and Gleason score.Kaplan-meier method was used to compare Overall Survival(OS) and biochemical relapse-free Survival(BRFS) of PSMA positive and negative groups.Finally,enzyme linked immunosorbent assay(ELISA) was used to detect the content of PSMA in serum of the two groups,and receiver operating curve(ROC) was used to evaluate the value of PSMA as a diagnostic marker.Results PSMA expression was positive in 221 of 270(81.9%) prostate cancer tissues and was positive in 24 of 50(48.0%) prostatic hyperplasia tissues.The positive rate of prostatic hyperplasia tissues was lower than that of prostate cancer group(P＜0.05) the positive expression rate of PSMA in patients with Gleason score >7 was higher than that in patients with Gleason score ≤7(P＜0.05).The median OS was 24 months and the median BRFS was 17 months in the PSMA positive group,which were significantly lower than those in the PSMA negative group(median OS:52 months and median BRFS:45 months),with statistically significant differences(P＜0.05).The serum PSMA content of prostate cancer patients was (17.97±6.66)μg/L,which was higher than that of prostate hyperplasia group[(7.90±5.03)μg/L],and the difference was statistically significant(P＜0.05).ROC results showed that when serum PSMA > 17.50μg/L was used as the cut-off value,the area under the curve(AUC) was 0.845,the diagnostic sensitivity was 71.1%,and the specificity was 82%.Conclusion The high expression of PSMA in prostate cancer tissue is closely related to Gleason score,and its expression is associated with worse prognosis in patients.Serum PSMA level can be used as a diagnostic indicator of prostate cancer.

Key words: prostate cancer, prostate specific membrane antigen, diagnosis, prognosis