OBJECTIVETo determine and compare the difference of cell apoptosis and proliferation in the transition and peripheral zones in the human prostate.

METHODSSeventeen normal prostate glands from organ donors were sampled from normal men according to McNeal/s zonal anatomy, and 20 hyperplastic transition zones obtained from prostatectomy specimens of BPH patients. Cell proliferation and Bcl-2 expression were assessed by immunostaining using PCNA and anti-Bcl-2 antibodies, while apoptotic bodies were specifically stained using TUNEL. Bcl-2 mRNA expression was detected by RT-PCR.

RESULTSIn the normal epithelium, the rates of cell proliferation and apoptosis were markedly decreased in the transition zone as compared with the peripheral zone. The proliferation index was significantly increased in the hyperplastic transition zone in BPH, while the apoptosis index significantly decreased in comparison with the normal prostate. Bcl-2 was significantly greater in the normal transition epithelium than in the peripheral zone, and over-expressed in the hyperplastic transition zone. There was a significant negative correlation between the Bcl-2 expression and the apoptosis of the epithelial cells in the hyperplastic transition zone (r(s) = -0.867, P < 0.01).

CONCLUSIONThe hyperplastic transition zone may result from both an increase of cell proliferation and a failure of cell apoptosis. Increased expression of Bcl-2 may participate in the BPH process by blocking cell apoptosis.