ABSTRACT
Necleolar organizer regions(NORs) ARE LOOPS OF DNA which transcribe to ribosomal RNA by RNA polymerase I. Since NOR-associated proteins are argyrophilic, silver staining method has been used for demonstration of AgNORs. The numbers and/or configurations of NORs may reflect the activities of cells in hyperplastic and neoplastic conditions. To evaluated the applicability of AgNORs in the diagnosis of hepatocellular carcinoma, the author had performed silver staining on the routinely processed, formalin-fixed, paraffin-embedded sections of 14 cases of normal liver(control), 23 cirrhotic liver, and 21 hepatocellular carcinoma. The results are summarized as follows: 1) The mean number of AgNORs per nucleus(mAgNOR) of normal liver, cirrhotic liver and hepatocellular carcinoma was 1.45+/-0.07, 2.53+/-0.38 and 5.52+/-1.63, respectively. The difference of mAgNOR between normal and cirrhotic liver, and between cirrhotic liver and hepatocellular carcinoma was statistically significant, respectively(p<0.01). 2) The percentage of nuclei showing five or more AgNORs per nucleus(pAgNOR) was 0.07% in normal liver, 7.59% in cirrhotic liver, and 60.49% in hepatocellular carcinoma. 3) AgNORs in hepatocellular carcinoma were large, pleomorphic and irregularly clumped, in addition to increase of mAgNOR and high pAgNOR. In conclusion, the increase of mAgNOR, high pAgNOR and large, irregular AgNORs are regarded as an additional helpful finding for the histopathological diagnosis of hepatocellular carcinoma.