Comparative flow cytometric deoxyribonucleic acid studies on exophytic tumor and random mucosal biopsies in untreated carcinoma of the bladder.

In 290 patients with untreated carcinoma of the bladder the deoxyribonucleic acid properties, as measured by flow cytometry, of 3 random mucosal biopsies were studied and compared to those of the exophytic tumors. Mucosal aneuploidy was found with few exceptions in aneuploid tumors only, and in a significantly lower frequency in aneuploid tumors of grade 2 than grade 3. The individual specificity of bladder tumors is emphasized by the observation that the level of ploidy was mostly the same in aneuploid mucosal biopsies as in the exophytic tumor. This is underlined further by the occurrence of cell populations of the same ploidy in different parts of the bladder mucosa. However, S-phase values of the concomitant intraurothelial lesions were significantly lower than those of the exophytic tumors. Therefore, we concluded that the process of evolution from malignantly transformed lesions, confined to the urothelium, to an exophytic or invasive tumor is dependent on a further elevated proliferation of the urothelial lesions.