CDKN2A and meningioma: In particular, homozygous deletions (homodel) of the cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B) genes on chromosome 9p21 have been associated with significantly shorter time to progression and is now a diagnostic criterion for World Health Organization (WHO) grade 3 meningiomas [4, 19, 27, 35, 46].