THE SIGNIFICANCE OF NUCLEOLAR ORGANIZER REGION (AGNOR) SCORE IN PREDICTING MENINGIOMA RECURRENCE

Background. Argyrophilic nucleolar organizer region (AgNOR) has been d emonstrated in recent studies of human brain tumors, including meningi omas. The authors used this technique in meningiomas to analyze whethe r the mean numbers of AgNOR per nucleus (AgNOR score) are related to t he recurrence rate or the proliferative potential of meningiomas. Meth ods. AgNOR staining technique was applied to paraffin-embedded section s of 60 meningiomas. Twenty of these specimens also were investigated immunohistochemically with monoclonal antibody (MoAb) against DNA poly merase alpha (Pol.alpha) and with MoAb Ki-67 to compare the AgNOR scor e with the proliferative potential. Results. There was a statistically significant difference between the AgNOR score in nonrecurrent mening iomas (2.48 +/- 0.73) and recurrent histologically benign meningiomas after gross total resection (3.20 +/- 0.96) (P < 0.02). The recurrence rate of tumors after gross total resection with an AgNOR score of 3.0 or more was significantly higher than that with an AgNOR score of les s than 3.0. The AgNOR score did not always correlate with Pol.alpha or Ki-67 score; the AgNOR score of malignant meningioma that had high pr oliferative score was not always high. Conclusions. This study indicat es that AgNOR staining appears to be a simple and useful method for es timating the probability of histologically benign meningioma recurrenc e even after gross total resection.