Modal DNA values of normal and malignant urothelial cells of the bladder in relation to nuclear size

In a study of the correlation between mean nuclear size and DNA content in urinary bladder carcinoma, the modal DNA values of cell suspensions from 125 biopsies, obtained from 86 patients with malignant or normal urinary bladder epithelium, were analyzed by flow cytometry (FCM). Light microscopic measurements of nuclear size were carried out on smears from the same material. The results were correlated to the histopathologic stage and grade. The mean nuclear volumes were significantly larger in diploid tumor cells than in cells of normal epithelium. Aneuploid tumors showed significantly larger nuclei than did diploid tumors. Although there was a significant correlation between increases in the nuclear volume and in the DNA content, there was some overlapping between various grades of malignancy: mean nuclear volumes in aneuploid grade 2 tumors did not differ from those in aneuploid grade 3 tumors. A combination of FCM and morphometry discriminated all but 16% of the tumors from the normal cases. It is concluded that FCM and morphometry are complementary and can be used for the objective characterization of urinary bladder carcinomas.