Relationship of epidermal growth factor receptor detectability with the A, B, H blood group antigens. Emphasis on normal and neoplastic urothelium.

The epidermal growth factor receptor (EGFR) is a glycoprotein that carries on its extracellular domains oligosaccharide chains, some of which are similar to blood group determinants. The author examined the expression of the EGFR using immunohistochemistry and three anti-EGFR antibodies with different fine specificities. These were applied to frozen sections from 120 tissue biopsies, including normal and neoplastic urothelium. The expression of blood group A, B, H determinants was also evaluated in the same tissues. Significant differences were noted, depending on the fine specificity of the anti-EGFR antibody, cellular differentiation, and the tissue donor's blood group. The most interesting finding was a reciprocal relationship between the reaction patterns obtained using antibodies with carbohydrate specificity and those with peptide specificity. These patterns were characteristic of cellular differentiation and suggested that the EGFR peptide determinants are detected in excess in immature and malignant cells that, however, appear deficient in oligosaccharide determinants. The combination of 'loss' of blood group antigen and an apparent overexpression of EGFR peptide determinants is indicative of invasive growth in transitional cell carcinomas.