Comparative analysis of DNA content in polyomavirus-infected urothelial cells, urothelial dysplasia and high grade transitional cell carcinoma.

OBJECTIVE To characterize the DNA content pattern in cytologically confirmed polyomavirus (PV)-infected urothelial cells and to compare it with DNA ploidy changes in cytologically diagnosed urothelial dysplasia and high grade transitional cell carcinoma. STUDY DESIGN We selected 200 bladder cytology specimens consisting of four groups with 50 patients each in the following cytologic categories: (1) no evidence of malignancy or dysplasia (controls), (2) PV, (3) urothelial dysplasia (UD), and (4) high grade transitional cell carcinoma (TCC-HG). For each case, two slides with 25-mm filter imprints were stained, one using the Papanicolaou method and the other using the Feulgen staining method. The DNA index (DI), proliferative activity (S + G2M) and degree of hyperploidy (> 5C) were evaluated using an image analysis system. RESULTS Using the Wilcoxon rank-sum test, statistically significant differences in the DI were found between the PV and UD groups (P = .008) and between the PV and TCC-HG groups (P < .0001). There was no significant difference in the DI between the PV and control groups. The S + G2M fraction for the PV group significantly differed from the control, UD and TCC-HG groups (all P < .0001). Between all four groups, the degrees of hyperploidy were significantly different as well (all P < .0001). CONCLUSION Cytologically confirmed PV-infected urothelial cells demonstrated a unique DNA content pattern with mildly elevated proliferative activity and a significantly dispersed hyperploid DNA content pattern. DNA analysis can help to differentiate PV infection from dysplasia and high grade carcinoma.