Relation between flow cytometric DNA distribution and pathology in human bladder cancer. A report on 69 cases

High-resolution flow cytometric measurements of cellular DNA content have been performed in 69 patients with transitional cell carcinomas of the urinary bladder. By selective sampling of cells at cystoscopy, mapping of the whole bladder could easily be performed, including the tumor as well as different areas of the surrounding normal-appearing mucosa. The cell-cycle distribution showed an increasing fraction of cells with S- and G2-phase content parallel to the World Health Organization (WHO) grade of the tumors, ranging from 1.7% S-phase cells in normal subjects to nearly 20% in tumors of WHO grade 3. WHO grade 2 tumors could be divided into two populations: (1) diploid, with a cell-cycle distribution similar to grade 1 tumors and low frequency of infiltration; and (2) aneuploid, with a high rate of infiltration and high fractions of S- and G2-phase cells. Furthermore, the aneuploid tumors could be subdivided into two main classes, one hypertriploid with high frequency of involvement of the surrounding normal appearing mucosa; and one hypotetraploid, with less frequency of such involvement and infiltration. It is concluded that by selective sampling and mapping of the bladder mucosa using flow cytometry, subclassification of this type of tumor can be performed rapidly, giving a reliable measure of the involvement of the bladder in the neoplastic disease and a biologic subclassification based on the type of DNA aberrations.