LOSS OF THE EXPRESSION AND LOCALIZATION OF INHIBIN ALPHA-SUBUNIT IN HIGH-GRADE PROSTATE-CANCER

Serum inhibin levels are elevated in postmenopausal women with granulo sa and mucinous epithelial tumors of the ovary. In contrast, functiona l deletion of the inhibin alpha gene in male and female mice results i n the development of primary gonadal granulosa/Sertoli cell tumors. Th e aim of this study was to determine whether inhibin alpha-subunit gen e and protein expression are altered in prostate cancer. Messenger rib onucleic acid expression was studied by in situ hybridization, and pro tein localization was studied by immunohistochemistry. Inhibin ol-subu nit messenger ribonucleic acid expression and protein localization wer e observed in the epithelium of tissues from men with benign prostatic hyperplasia, in regions of basal cell hyperplasia, and in nonmalignan t regions of tissue from men with high grade prostate cancer. In the m alignant regions of tissue from men with high grade prostate cancer, t he expression of the inhibin alpha-subunit gene was suppressed and was not detectable in poorly differentiated tumor cells. These results de monstrate that in contrast to ovarian granulosa cell tumors, inhibin a lpha gene expression is down-regulated in poorly differentiated prosta te cancer.