IDH1 and central nervous system cancer: Although some tissue biomarkers may be diagnostic and prognostic for gliomas such as MGMT promoter methylation and isocitrate dehydrogenase (IDH) mutations (46, 47), it is possible that any conclusions drawn about the immune landscape from analyses of tissue at the time of surgical resection may be too static to reflect the complex immune processes that are occurring throughout the disease course in response to anti-cancer therapy.