MTAP and glioblastoma: Crespo et al. reported that the chromosome 9p21.3 from the 21,978,443 bp to the 22,119,128 bp position was the most frequently deleted homozygous segments in GBM, which included CDKN2A (52%), CDKN2B and CDKN2BAS (48%), MTAP (26%), ELAVL2 (11%), and TUSC1 (11%)42.