IMMUNOLOCALIZATION OF GLYCOPROTEIN A-80 IN PROSTATIC-CARCINOMA AND PROSTATIC INTRAEPITHELIAL NEOPLASIA

A-80 is a mucin-like glycoprotein associated with exocrine differentia tion that shows little or no expression in normal exocrine cells and t ypical adenomas, but is upregulated in dysplasia and adenocarcinoma of certain organs. Its expression has not been systematically examined i n prostatic adenocarcinoma and its putative precursor, prostatic intra epithelial neoplasia (PIN). The authors applied a mouse monoclonal ant ibody against A-80 in paraffin-embedded sections from 103 cases of pro static carcinoma, 26 cases of nodular hyperplasia, 7 autopsy samples f rom normal young adult prostates, and 12 fetal prostates. All but one cancer reacted, although expression was heterogeneous; 75 of 103 stain ed extensively (>3+ on a 0 to 5+ scale) and strongly. Staining extent and intensity were independent of tumor grade, and tended to be strong even when focal. Seventy-seven of 84 fod (92%) of high-grade PIN and 38 of 52 loci (73%) of low-grade PIN stained for A-80; reactions were most extensive and intense in high grade PIN. Only 5 of 26 cases (19%) of hyperplasia reacted, and this consisted of weak to moderate staini ng in sporadic cells; the remainder were negative. Normal adult prosta tic epithelium did not express A-80 except for weak and inconsistent s taining in foci of inflammation and infarction; atrophic glands were n egative. Fetal prostate showed focally strong reactivity. These result s indicate that A-80 is selectively expressed in most cases of intraep ithelial neoplasia and prostate cancer, but is usually absent in benig n and hyperplastic epithelium. The upregulation of glycoprotein A-80 i n PIN and adenocarcinoma parallels observations in other organs, such as the breast and colon, suggesting that this is a significant oncodev elopmental molecule with potential clinical applications. Copyright (C ) 1996 by W.B. Saunders Company