RESUMO
The authors studied the expression of proliferating cell nuclear antigen (PCNA) and the number of argyrophilic nucleolar organizer regions (AgNORs) in 94 cases of various brain tumors and in 5 cases of normal brains. PCN was recognized immunohistochemically in paraffin sections by the monoclonal antibody PC-10. AgNORs could be demonstrated using the silver impregnation method. The PCNA index was not significantly different from the histological grading of glioma(glioblastoma multiforme: 41.40+/-29.14%, anaplastic astrocytoma: 35.00+/-41.02%, and low grade astrocytoma: 22.37+/-30.85%) and there was a wide range of staining even in the same tissue section. However, the AgNORs count per cell correlated well with the pathologic grading of glioma (glioblastoma multiforme : 3.19+/-0.71, anaplastic astrocytoma : 2.06+/-0.16, and low grade astrocytoma : 1.27+/-0.29) with statistical significance. In meningiomas, AgNORs were useful to differentiate benign meningiomas(1.25+/-0.19) and malignant meningiomas(1.78+/-0.35) The authors suggest that the AgNORs count is a faster, less expensive, and a more predictive method in the malignancy of brain tumors than the PCNA immunochemistry expression.