Correlation of the expression of Ki-67 with the histopathological features and grade of meningioma

BACKGROUND: Meningiomas are slow-growing and generally benign central nervous system tumors. They are classified into three grades based on histopathological findings. However, prediction of tumor cell proliferation and recurrence remains limited. Therefore, immunohistochemical examination is needed. This study aims to determine the correlation of the expression of Ki-67 with the histopathological features and grade of meningioma.METHODS: This observational study evaluated 60 patients with meningioma. Patients who had headache, vomiting, seizure, or increased intracranial pressure as well as intracranial meningioma were included. Immunohistochemical polyclonal Ki-67 antigen staining was independently assessed manually by two pathologists using the double-blind method. The relationship between the expression of Ki-67 and the histopathological features and grade of meningioma was evaluated using Spearman's rho and ANOVA (SPSS). P<0.05 was considered statistically significant.RESULTS: The proportion of women was higher than that of men (2.5:1). The mean patient age was 47.3 (range=10-76) years. Most tumors (60%) were located in the convexity. Ki-67 was expressed in grade II and III meningiomas, with the highest expression noted in anaplastic meningioma (50%). The Ki-67 expression significantly increased with the meningioma grade (P≤0.001). Among the major histopathological features, brain invasion was superior to mitotic activity (P≤0.001, correlation coefficient=0.651). Among the minor histopathological features, hypercellularity was superior to prominent nucleus and spontaneous necrosis (P=<0.001, correlation coefficient=0.693).CONCLUSIONS: The Ki-67 expression increases with the meningioma grade and appears significantly positive when there is brain invasion.