CELL-PROLIFERATION INDEXES, MORPHOMETRY AND DNA FLOW-CYTOMETRY PROVIDE OBJECTIVE CRITERIA FOR DISTINGUISHING LOW AND HIGH-GRADE BLADDER CARCINOMAS

Argyrophilic nucleolar organizer region (Ag-NOR) analysis, proliferati ng cell nuclear antigen (PCNA/PC10) and MIB-1 immunohistochemistry, nu clear morphometry and DNA flow cytometry have been performed on formal in-fixed, paraffin-embedded biopsies from 50 patients with transitiona l cell carcinoma of the urinary bladder. The mean AgNOR count was 6.01 for the 17 grade 1 (G1), 7.59 for the 21 G2 and 13.33 for the 12 G3 c arcinomas (p<0.001). The mean PCNA score was 15.03% for G1, 24.04% for G2 and 40.01% for G3 cases (p<0.001). The mean MIB-1 score was 11.31% for G1, 17.09% for G2 and 34.47% for G3 carcinomas (p<0.001). The mea n nuclear area was 35.53 mu m(2) for G1, 38.65 mu m(2) for G2 and 83.6 2 mu m(2) for G3 cases (p<0.001). Aneuploidy rates were significantly higher (91.7%) in G3 than in G2 (42.9%, p<0.01) or G1 cases (47.1%, p< 0.05) but not different for G1 versus G2 cases (p=0.94). While many ov erlaps of values were seen between G1 and G2 tumours, no overlaps were found between G3 and G1/G2 tumours. Significant differences of values were also found between pTa and invasive tumours (p<0.0001 for AgNOR count and PCNA score; p<0.001 for MIB-1 score and mean nuclear area; p <0.01 for DNA ploidy); however many overlaps were seen. Our findings i ndicate that the quantitative parameters obtained with different metho ds are associated with histological grade of bladder urotheliomas and may improve the grading reproducibility. In addition, the absence of o verlaps between G3 and G2/G1 carcinomas supports the tendency to class ify bladder urotheliomas in only two categories of malignancy.