Carbohydrate changes in colon carcinoma.

The colonic epithelium preferentially expresses only certain types of carbohydrate antigens. The most prevalent ones are the lacto-series type 1 (Gal beta 1,3GlcNAc) and type 2 (Gal beta 1,4GlcNAc) chain blood group-related substances, which can reside on both glycolipids and glycoproteins, and mucin-type O-linked structures such as Tn, T, and sialosyl-Tn, which reside exclusively on glycoproteins. This review focuses on the tissue expression in the colon of those carbohydrate tumour-associated antigens which have been most extensively studied and for which the epitope structure has been defined.