Mitomycin-C induced improvement in superficial bladder tumors: a morphologic and immunohistochemical evaluation.

Twenty bladder biopsies from ten patients with superficial transitional cell carcinoma were obtained prior to and following therapy with intravesical mitomycin-C. Each biopsy was evaluated histologically and immunohistochemically for A, B, H blood group antigen (BGA) expression. A, B and H blood group antigens were identified using monoclonal anti-A, B and H antibody and were localized with the avidin-biotin-peroxidase complex (ABC) technique. Particular attention was directed toward flat urothelial lesions and the urothelium adjacent to papillary tumors. Routine histologic evaluation showed improvement in post-therapy biopsies compared to corresponding pre-therapy biopsies in 7/10 cases but was equivocal in 3/10 cases. Immunohistochemical evaluation, however, showed improvement in all 10 cases, as judged by increased urothelial BGA expression. This increase in urothelial BGA expression after intravesical mitomycin-C therapy suggests a therapy induced improvement in dysplastic urothelium which was not uniformly evident on routine histologic examination.