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 co nfirmed polyomavirus (PV)-infected urothelial cells and to compare it with DNA ploidy changes in cytologically diagnosed urothelial dysplasi a and high grade transitional cell carcinoma. STUDY DESIGN: We selecte d 200 bladder cytology specimens consisting of four groups with 50 pat ients each in the following cytologic categories: (1) no evidence of m alignancy or dysplasia (controls), (2) PV, (3) urothelial dysplasia (U D), and (4) high grade transitional cell carcinoma (TCC-HG). For each case, two slides with 25-mm filter imprints were stained, one using th e Papanicolaou method and the other using the Feulgen staining method. The DNA index (DI), proliferative activity (S+G2M) and degree of hype rploidy (>5C) were evaluated using an image analysis system. RESULTS: Using the Wilcoxon rank-sum test, statistically significant difference s in the DI were found between the PV and UD groups (P=.008) and betwe en the PV and TCC-HG groups (P<.0001). There was no significant differ ence in the DI between the PV and control groups. The S+G2M fraction f or the PV group significantly differed from the control, UD and TCC-HG groups (all P<.0001). Between all four groups, the degrees of hyperpl oidy were significantly different as well (all P<.0001). CONCLUSION: C ytologically confirmed PV-infected urothelial cells demonstrated a uni que DNA content pattern with mildly elevated proliferative activity an d a significantly dispersed hyperploid DNA content pattern. DNA analys is can help to differentiate PV infection from dysplasia and high grad e carcinoma.