CDKN2B and meningioma: According to the latest World Health Organization (WHO) Classification of Tumors of the Central Nervous System (CNS), grade 3 should be assigned based on criteria for anaplastic meningiomas, which comprise malignant cytomorphology (anaplasia) that resembles carcinoma, high-grade sarcoma or melanoma; elevated mitotic activity; a TERT promoter mutation and/or a homozygous CDKN2A and/or CDKN2B deletion.