Random mucosal biopsies were taken from standard sites of the bladder in 25 patients with transitional cell tumors and 7 patients with benign prostatic disease. The tissues were examined for the presence of intraepithelial lesions, particularly hyperplasia, metaplasia, dysplasia and carcinoma in situ. The same biopsy specimens were used in an immunofluorescence assay to detect loss of blood group antigens. There was a significant correlation between the grade and stage of the tumor and the presence of intraepithelial lesions. In the follow-up period there was a higher rate of recurrence among patients with dysplasia and hyperplasia in mucosal biopsies.

Keywords: bladder tumors, blood group antigens, random biopsies