Clinical significance of silver binding nucleolar organizer regions(AgNORs) in transitional cell carcinoma of the bladder : The correlative study with flow cytometric SPF, PI and PCNA / 대한비뇨기과학회지

ABSTRACT

Nucleolar organizer regions(NORs) contain coding genes for ribosomal RNA and contribute the regulation of cellular protein synthesis. AgNORs numbers correlate with growth fraction and have been reported the AgNORs counts may have a diagnostic and prognostic utility in other human tumors. We investigated the diagnostic usefulness of AgNORs staining technique as a discriminant for malignancy and assessed the value as a potential method for the estimation of cell kinetics. In addition. we compared the AgNOR counts with flow cytometric analysis of ploidy, S-phase fraction, proliferation index, and PCNA expression rate. There was a statistically significant difference of AgNORs counts between superficial bladder tumor and invasive bladder tumor. But there was no relationship between the mean number of AgNORs per nucleus and histological grade. DNA aneuploid group was associated with higher AgNORs counts than diploid group, but the difference was statistically insignificant. The mean number of AgNORs per nucleus had significant relationship to SPF(r=0.43, p<0.05) and PI(r=0.41, p<0.05.) We concluded that this method alone does not offer a reliable histological discriminant for malignancy. Further studies are needed to confirm that AgNORs counting is a useful method for evaluating the proliferative activity and this technique may serve as a prognostic factor additional to the current histopathological grading criteria of the bladder cancer.