Comparative investigation of proliferation markers and their prognostic relevance in human meningiomas

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