HISTOCHEMICAL DEMONSTRATION OF ENDO-[beta]-GALACTOSIDASE SUSCEPTIBLE POLY-N-ACETYLLACTOSAMINE WITH THE BLOOD GROUP SPECIFICITIES IN PAPILLARY CARCINOMAS OF THE HUMAN THYROID GLANDS

Blood group ABH and related antigens are not expressed in normal thyroid glands. However, cells of thyroid papillary carcinoma, especially their luminal surfaces expressed ABH antigens in a manner compatible with the ABO blood group of patients. Sialyl Lewis a (CA 19-9) and sialyl precursor type 1 chain were likewise intensely and frequently expressed in these cells from most of the individuals examined. On the other hand, Lewis x, sialyl Lewis x and sialyl precursor type 2 chain were minor components of the carbohydrate antigens expressed in these cells. In contrast, type 2H, type 2A and presumably type 2B antigens were preferentially expressed in these cancer cells. Prior digestion with endo-β-galactosidase from Escherichia freundii eliminated or reduced the reactivity of monoclonal antibodies and lectins specific for these ABH and related antigens with carcinoma cells. Along with the elimination or reduction of staining with these reagents, binding sites with Griffonia simplicifolia agglutinin-II appeared in the corresponding tissue sites indicating the presence of poly-N-acetyllactosamine structures. These results suggested that poly-N-acetyllactosamine structure containing linear domain susceptible to endo-β-galactosidase digestion is a common and ubiquitous precursor of the blood group-related antigens and its synthesis is prerequisite for the oncofetal expression of these antigens in papillary carcinoma of the thyroids.