DNA aneuploidy in G1-urothelial carcinomas of the urinary bladder.

Thirty G1-urothelial carcinomas of the bladder were investigated using DNA cytophotometry. Specimens obtained by tumour resection and quadrantic biopsy were first fixed in formalin and then embedded in paraffin. The cells were then separated using the method developed by Hedley. The DNA content was established after Feulgen staining using a TV-based image analysis system. DNA aneuploidy, a marker for neoplasia, was investigated using the so-called stemline interpretation developed by Böcking. This method compares the DNA content of the G0/1 tumour cells in the cell population to be analysed with the reference cell population, using the Kolmogoroff-Smirnow test (p < 0.001). On this basis, 23 tumours (76.6%) were DNA aneuploid, whereas if DNA aneuploidy is defined (as conventionally) as a DNA content of > 2.2c, only 17 tumours (56.6%) were found to be DNA aneuploid. The mean stemline value was 2.4c (range 1.85-3.96). By using a more precise TV-based image analysis system and this new DNA stemline interpretation, the rate of detection of DNA aneuploidy was improved by 20%. The diagnosis of G1-urothelial carcinomas by DNA cytophotometry is at least 25% more sensitive than that using conventional cytology (20-50%). We suggest that modified DNA cytophotometry could be a useful, additional diagnostic tool in examining doubtful urinary samples.