In this WHO classification, loss of H3K27me3 is indicative of aggressive meningioma behavior and recurrence, and homozygous deletions of CDKN2A/B and mutations of TERT promoter (pTERT) are criteria for Grade 3 meningiomas since they are linked to an increased risk of recurrence [8,45,46]. Here, CDKN2A is linked to meningioma.