CDKN2A and meningioma: The first scheme assigns one point to each of the specific copy number alterations (1p, 3p, 4p/q, 6p/q, 10p/q, 14p/q, 18p/q, 19p/q, CDKN2A/B), which are present with another point for four to nineteen mitoses per 10 high-powered fields or two points for 20 or more mitoses, and meningiomas with four or more points are classified as integrated grade 3 [97].