Background: The value of nucleolar organizer regions (NOR) visualized by silver staining (AgNOR) for the histologic differentiation, pathologic staging, and estimation of growth rate was assessed by the investigation of paraffin sections from 58 lung adenocarcinomas. AgNOR consist of NOR-associated proteins, and the number of AgNOR might be related to proliferative activity.
Methods: In lung adenocarcinoma, the growth rate can be measured by means of chest radiographs. Using this technique, the authors studied the correlation between the mean number of AgNOR and growth rate.
Results: The mean number of AgNOR ranged from 1.8 to 6.3 (mean +/- standard deviation, 4.0 +/- 0.8). Neither the degree of histologic differentiation nor the pathologic staging was related to the AgNOR count. The tumor growth rate was estimated on the basis of the doubling time in the chest radiographs of 13 patients. The doubling time ranged from 80 to 760 days. There was a high inverse correlation between the AgNOR count and the doubling time (r = -0.910; P less than 0.001).
Conclusions: Thus, it appears to be possible to use the mean number of AgNOR as an index of proliferative activity.