Expression of maspin and glutathionine-S-transferase-π in normal human prostate and prostatic carcinomas

BACKGROUND: Maspin and glutathionine-S-transferase-π (GST-π) are both involved in tumor suppression activity. Maspin expression functions as an inhibitor of tumor progression preventing the local invasion and metastatic spread of prostate cancer ells. GST-π has an essential role in the inactivation of xenobiotic agents and protection from oxidative stress and in resistance to chemotherapy. Furthermore, a recent experimental evidence indicated that maspin and GST-π may directly interact in the protection of the prostatic cells from oxydative damage. DESIGN: Maspin and GST-π expression were assessed in needle core and transurethral resection prostatic biopsies from 42 patients (34 with carcinoma, and 8 with normal prostate gland) using immunohistochemical methods. RESULTS: Maspin and GST-π were strongly and consistently coexpressed in the cytoplasm of basal cells of normal prostatic glands, whereas normal luminal cells were inconsistently weakly positive. Prostatic adenocarcinomas overexpressed maspin in 27/34 cases (79%). In the majority of the cases, the subcellular distribution showed a predominance of nuclear expression. In contrast, only 1 case of prostatic carcinoma expressed GST-π. CONCLUSION: Consistent coexpression of maspin and GST-π was observed in basal cells of the prostatic glands, which could be used as an additional immunohistochemical test in the evaluation of prostatic malignancy. Prostatic adenocarcinomas express maspin in an aberrant nuclear distribution without coexpresion of GST-π. These results indicate a deregulation of expression of maspin and GST-π in prostatic adenocarcinomas.