Purpose: The human prostate and seminal vesicles are both androgen-dependent accessory sex organs. They share the same blood supply, exposure to carcinogens and androgen stimulation. Despite these similarities, the incidence of cancer in these two organs is vastly different. We analysed the impact of various factors on the carcinogenesis of these tissues. Materials and Methods: In 20 specimens each of seminal vesicles and prostatic tissue, expression of metallothioneine, glutathione S-transferase (GST), chromogranin-A, TGF-β1, bcl-2 and MIB-1, as well as apoptotic rate were assessed by immunohistochemistry. In 10 specimens each, nuclear morphometry and two-dimensional gel electrophoresis of nuclear matrix proteins (NMP) were performed. Results: NMP composition analysis demonstrated that both tissues had a similar NMP composition. Tissue-specific NMPs consistently present in all specimens of each tissue could not be demonstrated. Nuclear morphometry showed a significantly greater heterogeneity in nuclear shape in the seminal vesicles than in the prostate. Cell turnover was higher in the prostate than in the seminal vesicles. TGF-β1 seems to be more important for the regulation of cell turnover in the seminal vesicles than bcl-2. Neuroendocrine cells were not detected in the seminal vesicles, while GST-expression was similar in both tissues. Metallothioneine expression is lower in the seminal vesicles than in the prostate. Conclusions: Expression of tumor-protective proteins cannot be regarded as the main reason for the vastly different cancer incidence in the seminal vesicles and prostate. The low cell turnover and heterogeneous nuclear morphology of the seminal vesicles may suggest that the seminal vesicle tissue is well-differentiated.
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