NF2 and meningioma: As expected, NF2 alteration was more often present in WHO grade 2 and 3 tumors than in grade 1 (respectively 18/27 vs. 11/36, p = 0.01, Figure 3C) and in the skull convexity meningioma in comparison to the skull base ones (18/30 vs. 4/21 p = 0.0037).