No correlation between the outcome and the Ki-67 index was found in 600 cases of benign meningiomas.9 The principal limitation of the Ki67 index seems to be the lack of standardization of the technique and difficulties in defining cut-off values.9,29,30 Our study confirms an important role of the Ki67 index in meningioma grading, suggesting different cell proliferation rates in different meningioma grades (Figure 1). This evidence concerns the gene MKI67 and meningioma.