CDKN2B and glioblastoma: We found no evidence for an association between the two glioma risk SNPs in the 9p21.3 region and DNA methylation of CDKN2A or CDKN2B. However, homozygous deletion of the chromosomal region 9p21.3, harbouring CDKN2A, CDKN2B, CDKN2B-AS1, and MTAP, is a frequent event in glioblastoma [15].