[Studies on nuclear DNA content in bladder cancers using flow cytometry]

This study was designed to evaluate the clinical relevance between the DNA ploidy and histopathology, and the incidence of the DNA heterogeneity in patients with bladder cancers. Flow cytometry(FCM) was used to study the DNA ploidy in 63 patients who underwent total cystectomy. The DNA ploidy and DNA index were analyzed by FCM in total 478 paraffin embedded samples (7.6 samples per case on the average). The DNA ploidy of 52 bladder cancers, that had coexisted after total cystectomy, showed that 24 cases, 46% were DNA aneuploid and 18 cases, 35% had DNA heterogeneity. The other 11 cases which were found to be pT0 after cystectomy were all DNA diploid. There were significantly good correlation among DNA ploidy pattern and intravesical involvement (lymph-duct involvement and venous involvement), but were not among the DNA ploidy pattern and tumor grade and stage. With regard to the evaluation of two vertically devided samples of tumors, DNA aneuploid had been not always recognized in the deeper samples, therefore, the author did not determine that there was good correlation between the DNA ploidy and the tumor invasion. In lymph node metastases, the 39 diploid tumors had given rise to lymph node metastases in only 5 cases(13%), whereas 11 cases(46%) of the 24 aneuploid tumors had metastasized(p < 0.01). Eleven of 16 lymph node metastases were DNA diploid and the others were DNA aneuploid. These data suggest that although the incidence of DNA heterogeneity in bladder cancers (35%) is thought to be relatively small, the DNA ploidy will be able to be the important prognosticating factor in bladder cancers.