Despite these promising preclinical results, the first clinical use of azacitidine given as therapy of 12 heavily pretreated patients with IDH1/2-mut recurrent gliomas with astrocytic or oligodendroglial histology showed only minimal activity: no patient achieved a radiographic response, while five (41.7%) had disease stabilization, of whom 2 (16.7%) lasting for more than 18 months [68]. This evidence concerns the gene IDH1 and central nervous system cancer.