Flow cytometric analysis of DNA content of deparaffinized nuclei in urinary bladder carcinomas

Abstract

A consecutive series of 230 patients with transitional cell carcinoma of the urinary bladder was analyzed with respect to the DNA content of the primary tumor, as determined by flow cytometry on material obtained from paraffin blocks. A new method for this analysis was elaborated, based on proteolytic digestion with protease (type VII, Sigma) and density separation of the nuclei by Percoll centrifugation. The method provided DNA flow histograms with less baseline debris and a smaller coefficient of variation in the peaks than published techniques. In eight of 70 cases tested (11%) the method revealed aneuploid peaks that were not distinguished with the original technique and in 197/230 case (86%) interpretable DNA histograms were obtained. The distribution of diploid and aneuploid tumors in different grades and T categories was assessed. None of the grade 1 tumors was aneuploid; 11% of grade 2A, 63% of grade 2B and 83% of grade 3-4, respectively, were aneuploid. The corresponding figures for categories Ta, T1, T2, T3 and T4 were 16, 55, 72, 65 and 100%, respectively.