MTAP and central nervous system cancer: Therefore, the TP53 R175H mutation as well as the CDKN2A/B and MTAP exons 5-8 losses seem to be acquired events through time, the latter two being markers of GB progression and poor prognosis.16,27,28 Two patients with glioma whose tumors harbored 2 different FGFR alterations -FGFR3 fusion and FGFR3 mutation- have been described, highlighting the complex biology of these tumors.29