IDH1 and central nervous system cancer: Glioma classification in humans is based on 2021 World Health Organization criteria, including genotypic, molecular and phenotypic tumor features, describing entities in which the presence of isocitrate dehydrogenase 1/2 (IDH1/2) mutations and 1p/19q codeletion status are considered important predictors of positive prognosis and longer overall survival than are found in patients carrying the wild‐type IDH1/2 gene.5, 6, 7