Blood group ABO and Lewis antigen expression during neoplastic progression of human urothelium. Immunohistochemical study of type 1 chain structures.

The deletion of blood group ABO antigen expression in bladder carcinoma has attracted attention because of its potential as a prognostic parameter. Based on recently produced monoclonal antibodies against blood group antigens, it has become possible to elucidate the carcinoma-associated modulation of these antigens at a molecular level. In this study we have used a panel of monoclonal antibodies (H, Lea, Leb, A, ALeb) that are specific to type 1 chain structures. By the use of an immunohistochemical method, the histologic and cytologic location of these antigens in the urothelium was studied in 25 biopsies from transitional cell carcinomas and compared to 21 previously examined normal biopsies. Urothelial blood group reactivity was compared to Lewis and secretor status. The authors found a series of events associated with neoplastic progression of noninvasive urothelium: a disruption of the orderly stratification of blood group antigens in different cell layers; cytostructural relocation of cytoplasmic antigens to the cell surface; loss of correlation between urothelial blood group antigens and secretor status; and gradual deletion of antigens. In the invasive tissue these events were followed by a total deletion of A and H isoantigens and uniform expression of Lewis b and sialyted Lewis a antigen. These findings indicate that there is a complex modulation of blood group antigen biosynthesis associated with the neoplastic progression of the human urothelium.