Characterization of squamous cell bladder tumors by flow cytometric deoxyribonucleic acid analysis: a report of 100 cases.

We studied 100 cases of squamous cell carcinoma of the bladder by flow cytometry after cystectomy. Tumors were classified according to the deoxyribonucleic acid profile into diploid or aneuploid. Proliferation of the tumors was assessed from the proportions of S-phase cells. The flow cytometric data were correlated to the histopathological stage and grade. Grade 1 tumors could be subdivided into diploid and aneuploid in 60 and 40% of the cases, respectively, while 95% of the grade 2 and all grade 3 tumors were aneuploid. Diploid tumors had low proliferation rates, while aneuploid tumors had significantly higher values. A high frequency of muscle invasive diploid squamous cell tumors was noted. Tumor heterogeneity was studied by comparing cell material from superficial and deep tumor areas, which were in agreement in 77% of the cases. By comparing biopsy material with that obtained by bladder washings, biopsy material yielded better information regarding deoxyribonucleic acid ploidy in half of the aneuploid tumors. These results indicate that flow cytometry offers an additional objective method to characterize squamous cell carcinoma.