IDH1 and central nervous system cancer: 12 The majority of studies were conducted on IDH mutated gliomas, which show an association with a more unfavorable prognosis. 13-20 Several studies have also been conducted on CDKN2A/B loss in IDH wildtype glioblastoma. 21-25 These studies suggest that the deletion status of CDKN2A/B may be associated with overall survival and the efficacy of therapy in specific subpopulations. 21-24, 26 Nonetheless, these studies did not consider the various molecular subtypes of glioblastoma. 21, 23, 26