Blood group antigen synthesis and degradation in normal and cancerous colonic tissues

摘要: ABH antigens are expressed by colonic epithelial cells throughout the colon during fetal life but only in proximal segments adulthood. Malignant and premalignant tumors frequently exhibit reappearance (distal lesions) or deletion (proximal occasionally express incompatible A B substances. Mechanisms governing these developmental cancer-associated alterations unknown. Therefore, experiments were performed to assess activities of biosynthetic (glycosyltransferase) degradative (glycosidase) enzymes normal cancerous tissues distal colon. In mucosa, A, B, H transferase similar segments. Analysis enzyme substrate affinities product characterization confirmed that transferases gene-specified human serum. Glycosidase also comparable Cancers had lower compared with paired mucosa. Thus, absence antigen expression is not caused insufficient glycosyltransferase activity excessive glycosidase activity.