OBJECTIVETo investigate the expressions of the EZH2 protein and EZH2 mRNA in human prostate cancer (PCa) and their correlation with the clinicopathologic parameters.

METHODSA tissue microarray (TMA) was constructed, which contained 48 dots of formalin-fixed paraffin-embedded tissue samples of human PCa. The expressions of the EZH2 protein and EZH2 mRNA in the samples were detected by immunohistochemistry (EnVision) and in situ hybridization (ISH). Another 15 cases of human benign prostate hyperplasia (BPH) and 12 cases of human prostate intraepithelial neoplasia (HGPIN) were taken as controls.

RESULTSThe positive rates of the EZH2 protein and mRNA were significantly higher in PCa than in BPH and HGPIN (87.5% vs 13.33% and 16.67%, 81.25% vs 6.67% and 16.67%, P < 0.05). The positive expression of the EZH2 protein was 96.67% and 72.22% in the Gleason score > or = 7 and Gleason score < or = 6 groups, respectively, with significant differences between the two groups (P < 0.05). The positivity of the EZH2 protein was significantly related to the TNM stage, increasing with tumor progression (P < 0.05), but not to age and serum PSA (P > 0.05), and so was that of EZH2 mRNA to TNM stage (P < 0.05), but not to age, serum PSA and Gleason score (P > 0.05). When the above characteristics were regarded as two-level discrete variables, both the EZH2 protein and EZH2 mRNA showed statistically significant differences in the positive expression rate (P < 0.05).

CONCLUSIONThe over-expressions of the EZH2 protein and EZH2 mRNA may play an important role in the pathogenesis and progression of PCa and provide some reference indexes for estimating the malignancy, progression and prognosis of PCa.