STUDY ON NUCLEOLAR ORGANIZER REGIONS IN BLADDER NEOPLASM

Abstract

Quantification of the argyrophilic nucleolar organizer regions (AgNORs), using a one-step silver colloid method, was made in proliferative urothelial lesions including neoplasm of the rat urinary bladder induced by 0.05% N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN) and of the human urinary bladder. The mean numbers of AgNORs in various experimental lesions in rats given BBN for 5-30 weeks in drinking water were: nontreated urothelium (n=6), 1.26±0.09; urothelium outside focal lesions (n=10), 1.75±0.10; simple hyperplasia (n=10), 2.01±0.15; papillary or nodular (PN) hyperplasia (n=10), 2.15±0.19; papilloma (n=5), 2.37±0.12; and transitional cell carcinoma (TCC) (n=5), 3.52±0.23. There was a significnat difference in the mean number of AgNORs between any two groups (p<O.05), except for simple hyperplasia vs PN hyperplasia (p=0.085). In various proliferative lesions of human biopsy and resected samples, the mean numbers of AgNORs were: normal urothelium (n=8), 1.71±0.08; proliferative cystitis (n=14), 1.79±0.18; hyperplasia (n=8), 1.76±0.23; mild dysplasia (n=5), 2.15±0.36; moderate dysplasia (n=13), 2.61±0.27; severe dysplasia (n=6), 3.46±0.57; G0 of TCC (n=9), 1.95±0.17; G1 of TCC (n=16), 2.39±0.20; G2 of TCC (n=21), 3.33±0.31; G3 of TCC (n=15), 4.68±0.51; and carcinoma in situ of TCC (n=10), 3.61±0.52. These results indicate that there is a stepwise increase in number of AgNORs from normal urothelium through various grades of preneoplastic lesions to carcinoma, and that the number of AgNORs reflects a proliferative activity of the experimental and human urinary bladder lesions, which is related to the grade of cancerous tissue. Moreover, cancer chemotherapy induced changes of AgNORs number in bladder cancer and such changes were remarkable in the tissue of patients with a good response for chemotheray. Thus, quantification of AgNORs could be a new method for the histopathological assessment of urothelial proliferation in both human and rat urinary bladder.