Characterization of bladder tumours by multiparameter flow cytometry with special reference to grade II tumours

Sixty-three human transitional cell carcinomas of the urinary bladder were studied by multiparameter flow cytometry (FCM). The cellular DNA content, the cellular protein content, the fraction of cells in S phase, and the nuclear size were registered and correlated to histological grade (WHO) and histologically determined infiltration through the basement membrane. Aneuploidy was found in the great majority of grade III tumours, but in only 24% of grade II tumours. A new, combined variable, viz. the cellular DNA to protein ratio, indicated a possibility for further subdivision of the tumours. Grade II tumours, which constitute a rather heterogeneous group with regard to prognosis, could be classified in two subgroups: One group of diploid tumours with the FCM characteristics of grade I tumours, and another group of diploid and aneuploid tumours with the characteristics of grade III tumours. Infiltration was most frequently seen in the latter subgroup. The putative prognostic relevance of such a subdivision will be the subject of a future study. Compared to FCM measurement of DNA alone, multiparameter FCM, including measurement of the total cellular protein content, has given additional information that may be of prognostic value.