Objective: In human meningiomas, histology alone does not always predict the clinical outcome. Proliferative activity has therefore, become a potential tool in the histopathological grading of these tumors. The aim of this study was to investigate different Ki67 antibodies on meningiomas, to compare their proliferation indices (PI) and with other proliferation markers, such as S-phase fraction and mitotic activity, and to see whether these factors correlate with histological tumor grade.
Material and methods: The study included 43 meningiomas graded according to the criteria of WHO and Jääskeläinen et al. [1985, 1986]. Paraffin sections were used for immunohistochemical detection of Ki67 antigen and flow-cytometric determination of S-phase fraction.
Results: The PIs displayed an overall increase with increasing histological grade, however, the range of values for benign, atypical and anaplastic meningiomas were wide, resulting in considerable overlap between the groups. There were for the most significant correlations between the different proliferation markers.
Conclusions: Ki67-equivalent antibodies and S phase fraction have no advantage over counting mitoses to assess the proliferative activity in meningiomas. Thus, mitotic activity justifies its role in meningioma grading.