Prognostic significance of silver-binding nucleolar organizer regions(AgNORs) in prostatic carcinoma: The correlative study with flow cytometric S-phase fraction, proliferation inde and proliferating cell nuclear antigen(PCNA) expression rate / 대한비뇨기과학회지

ABSTRACT

The nucleolus plays a vital role in control of cell proliferation and protein synthesis. Nucleolar organizer regions (NORs), segment of DNA closely associated with nucleoli, contain coding genes for ribosomal RNA and contribute the regulation of cellular protein synthesis. Detectable by the argyrophilia of associated proteins, silver-binding nucleolar organizer regions (AgNORs) numbers correlate with growth fraction and have been reported the AgNORs counts may have diagnostic and prognostic utility in other human tumors. We investigated further the diagnostic usefulness of the AgNORs technique as a discriminant for malignancy. In addition, we compared the AgNORs counts with flow cytometric analysis of ploidy, S-phase fraction (SPF), proliferation index (PI), and proliferating cell nuclear antigen (PCNA) expression rate. Also, we assessed this technique as a possible prognostic indicator for prostatic carcinoma. There was no linear relationship between the mean number of AgNORs per nucleus versus Gleason histologic grade (r=0.093, p=0.578) and DNA aneuploid group was associated with higher AgNORs counts than diploid group in clinical stage C and D, but the differences were statistically insignificant. The mean number of AgNORs per nucleus had no significant relationship to SPF (r=-0.09, p=0.58) and PI (r=-0.119, p=0.477). Also, there was no significant relationship between mean number of AgNORs and PCNA (r= 0.205, p=0.217). We evaluated the probability, of survival for 29 patients with close follow-up. There was no significant difference of survival between high and low AgNORs number group, even after combined stratification by Gleason grade (Kaplan-Meier analysis with generalized Wil-coxon test). We conclude that this method alone does not offer a reliable histologic discriminanl for malignancy in prostatic tumor, and it is concluded that this technique is of no value in predicting prognosis for prostatic carcinoma.