[Cell kinetics of human meningiomas and neurinomas--Ki-67 PAP stain]

Seventeen surgically resected meningiomas and six neurinomas including one neurofibroma were labelled with frozen sections using a monoclonal antibody Ki-67, which reacts with a nuclear antigen expressed by proliferating cells. In thirteen classic non-malignant meningiomas, the percentage of stained cells ranged from 0.2 to 3.2% (mean, 1.4%). Those of three recurrencies consisted of anaplastic one and another one with anaplastic component, and one hemangiopericytic type ranged from 2.9 to 8.7% (mean, 4.8%). Four classic non-malignant neurinomas and one neurofibroma had the range from 0.3 to 2.7% (mean, 1.3%). However, one anaplastic neurinoma showed the largest fraction (13.0%) of positive nuclei in all these tumors. These results show, in conclusion, that the determination of Ki-67 immunoreactivity in the cell nuclei of meningiomas and neurinomas can contribute to more objectiveness in histological grading and the higher positive rate could be one of various factors relating to recurrence.