Expression of Lewis carbohydrate antigens and chromogranin A in human prostatic cancer.

The prostate specific antigen (PSA) content, the neuroendocrine differentiation and the Lewis(y) and the expression of related carbohydrate antigens in pathological prostatic tissues were determined. These included 13 cancers and 11 benign hyperplasias. PSA is expressed strongly in hyperplastic and poorly in neoplastic tissues. The neuroendocrine differentiation detected by a monoclonal antibody directed against chromogranin A (CgA) is a frequent event in carcinomas and rare in hyperplastic prostate. The Lewis(y) and related carbohydrate antigens, evaluated by the reactivity of the tissues to two monoclonal antibodies MAbB3 and MAbB1, are expressed in a considerable percentage in malignant tissues of prostate and only occasionally in benign lesions. Our results suggest that immunoblotting with antibodies against CgA, B3 and B1 on the tissues, obtained after surgery, may be useful to obtain more information on the neoplastic transformation of human prostate. Furthermore, the expression of Lewis(y) and related carbohydrate antigens on the surface of prostate cancer suggest that, following a clinical trial, an immunotoxin combination of MAbB3 or MAbB1 and Pseudomonas exotoxin, may be used in the treatment of prostate cancer.