Characterization of bladder carcinomas by flow DNA analysis.

Three-hundred and three consecutive newly detected bladder tumours were studied by DNA flow cytometry. The tumours were classified as diploid or aneuploid. The degree of aneuploidy was determined and the existence of more than one aneuploid cell peak was considered. Proliferative properties of the tumours were assessed from the proportion of S-phase cells. The majority of grade 1 tumours were diploid and grade 3 tumours aneuploid with few exceptions, while half of the grade 2 tumours were diploid or aneuploid. Ta tumours differed from T1 tumours in that they had a lower frequency of aneuploid cases, a lower proliferation rate and fewer cases with more than one aneuploid cell line. The proportion of S-phase cells increased with grade and stage. More than one aneuploid cell line was most frequently found for muscle-invasive tumours and in carcinoma in situ. A subdivision of bladder tumours based on the DNA pattern is presented.