摘要Objective:Prostate secretory protein of 94 amino acids (PSP94) is a target gene of the EZH2 transcriptional repressor and is often downregulated in prostate cancer; however, its prognostic value is disputed. Methods:Immunohistochemical analysis of a tissue microarray of 12, 432 prostate cancer specimens was performed to evaluate PSP94 expression. Correlation of PSP94 expression with tumor phenotype, patient prognosis,TMPRSS2:ERG fusion status, EZH2 expression andPTEN deletion was studied. Results:PSP94 expression was increased in benign prostatic hyperplasia; however, it was downregulated in 48％ and negative in 42％ of the 9, 881 interpretable prostate cancer specimens. The loss of PSP94 expression was inversely correlated to EZH2 expression (P < 0.0001) and largely unrelated to the ERG status, but strongly correlated with high Gleason grade, advanced tumor stage, and nodal metastasis (P <0.0001 each). The fraction of PSP94-negative cancer specimens increased from 40％ in pT2 to 52％in pT3b-pT4 (P < 0.0001) and from 40％ in Gleason 3+3 = 6 to 46％ in Gleason 4+3 = 7 and 60％ in Gleason≥4+4 = 8 (P <0.0001). Loss of PSP94 was linked to early prostate-specific antigen recurrence, but with little absolute effect (P < 0.0001). However, it provided additional prognostic impact in cancer specimens withPTEN deletion. Loss of PSP94 deteriorated prognosis of cancer patients withPTEN deletion by more than 10％ (P < 0.0001). The combination ofPTEN deletion and PSP94 loss provided independent prognostic information that was observed in several subgroups defined by classical and quantitative Gleason grade. Conclusions:The results of our study suggest that combined PSP94/PTEN analysis can be potentially used in the clinical prognosis of prostate cancer.