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-ram 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 pat- tern 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.