Glycophenotype of prostatic carcinomas

Abstract

The factors that affect the progression of prostatic carcinoma are poorly understood, but it is known that carbohydrate antigens on the tumour cell surface play a role in the transforming and metastatic processes. The present report aimed to perform a comparative, lectin-histochemical study of benign and carcinomatous prostates, using a battery of 15 lectins, in combination with monoclonal antibodies against Lewis antigens, and a semi quantitative study, to investigate the changes in glycosylation patterns that occur in prostatic carcinoma. Blocks from 27 necropsy cases of prostatic carcinoma were sectioned and stained with H&E, 15 biotinylated lectins chosen to probe for a wide range of oligosaccharide sequences within several categories of glycoprotein glycans, using a lectin-biotin avidin–peroxidase method, and monoclonal antibodies against Lewis^a, sialyl Lewis^a and sialyl Lewis^x antigens. The glycophenotype of prostatic carcinoma differed from that of the noncancerous prostate in revealing more intense staining with the following lectins (AAA, UEA-1, DBA, WFA, VVA, HPA, BSA-1_B4, MPA, ECA, AHA and CTA), while the binding patterns of (GNA and NPA) were almost similar in both prostatic carcinoma and the noncancerous prostate. Lewis antigens are found to be expressed in prostatic carcinomas but not in the noncancerous prostate. The observations of this study suggest that the gylcophenotype of transformed prostatic cells was modified. It showed a moderate increase in, and changing patterns of, fucosylation and galactosylation, increased branching of side chains and sharp rise in 2 deoxy, 2 acetamido galactosylation and masking process by sialylation, especially by α2–3 and α2–6 linkages. O-glycans seems to play an important role in the glycosylation patterns found in prostate carcinoma cells.