Pronounced changes in the expression of ABO and
Lewis antigens have been observed in
transitional cell carcinomas compared with normal urothelium. These changes are associated with changes in the activity of
blood-group gene-encoded
glycosyltransferases. This paper describes the correlation between
blood-group antigen expression and the activity of
glycosyltransferases in
transitional cell carcinomas. Examined individuals were A1A2BO, Lewis, and secretor typed by the use of blood and saliva. The activity of alpha-2-, and alpha-4-L-fucosyltransferases as well as the
alpha-3-N-acetyl-D-galactosaminyltransferase were determined as p-moles of labelled
sugar incorporated by
Lacto-N-biose I and
2'-fucosyllactose, respectively, per 100,000
carcinoma cells. In 3 non-secretors whose erythrocytes types as Le(a+b-), the
alpha-2-L-fucosyltransferase activity was similar to that in 3 secretors, and the Leb
antigen could be demonstrated to be present by
monoclonal antibodies, both by immunohistological and immunochemical means. In 11
tumors from A individuals, the A1-transferase was severely reduced in 9 individuals who showed a loss of A
antigen expression, and present in 2 individuals with A
antigen expression in cytoplasmic vesicles. In conclusion, we demonstrate a good correlation between individual
glycosyltransferase activity and expression of
blood group Leb and loss of expression of
blood group A in
transitional cell carcinomas. Immunostaining of neutral
glycolipids separated by TLC showed the Leb-active
glycolipids to be simple hexa-saccharides in both secretors and non-secretors.