OBJECTIVETo investigate the expression of programmed cell death 5 (PDCD5) in tissues of normal human prostate (NP), benign prostatic hyperplasia (BPH), and prostate cancer (PCa) in order to assess the clinical role of PDCD5 in PCa.

METHODSPDCD5 expression was determined by EnVision immunohistochemical staining in formalin-fixed and paraffin-embedded specimens obtained from 12 subjects with NP, 22 with BPH, and 22 with PCa. In addition, PCa cases were classified as low/middle-risk (Gleason sum < or = 7) and high-risk (Gleason sum >7) on the basis of Gleason grade. Positive expression rates and intensity of PDCD5 protein were observed under light microscope and analyzed with computer imaging technique. Expression of PDCD5 was compared among different prostatic tissues.

RESULTSThe expression of PDCD5 was significantly lower in tissue of PCa than in tissues of NP and BPH (P<0.01). However, there was no significant difference in PDCD5 expression between tissues of NP and BPH. In addition, the expression of PDCD5 was further downregulated with the increase of Gleason sum in PCa.

CONCLUSIONSBy downregulating apoptosis, low PDCD5 expression may play an important role in the occurrence and development of PCa. PDCD5 is supposed to have a potential clinical value to be a new predictor of progression and target of gene therapy in PCa.