The significance of the nucleolar organizer regions(NORs) in prostatic adenocarcinoma

Suh, Hong Jin; Yoon, Jai Young

Abstract

NORs are loops of DNA which occur in nucleoli and which posses ribosomal DNA genes. Ribosomal DNA genes transcribe to ribosomal RNA by RNA polymerase I and are of vital significance in the ultimate synthesis of protein. Proteins associated with the NORs are stained with silver nitrate (Ag-NORs). Ag-NORs were studied in various tumors and might reflect the activity of cells and might be an indicator of the degree of malignancy in tumors. Specimens of prostate obtained by transurethral resection or fine needle biopsy were examined with regard to the number and area of NORs in order to find out whether the above mentioned two parameters reflect proliferative activity in 23 cases of prostatic adenocarcinoma and 10 cases of benign prostatic hyperplasia as controls. The mean number of Ag-NORs in BPH, well, moderate and poorly differentiated adenocarcinoma was 1.24+/-0.10 (mean+/-SD; n=10), 1.87+/-0.23 (n=6). 2.08 J=0.28 (n=10). 4.02+/-0.22 (n=7). respectively. In each group, significant difference was found statistically (p<0.05) except between well and moderate differentiated adenocarcinoma. The mean area of Ag-NORs calculated by morphometry in BPH, well, moderate and poorly differentiated adenocarcinoma was 5.40+/-1.8 um2, 7.84+/-3.68 um2. 14.02+/-4.95 um2, 23.99+/-6.94 um2, respectively and significant difference was found statistically in each group (p<0.05). We concluded that the number and area of NORs increased with degree of malignancy and may reflect proliferative activity of cells in prostatic adenocarcinoma. Further investigations may be needed to confirm whether the number or area of Ag-NORs may be available as a prognostic factor for patient`s survival.