This new classification strongly stresses the relevance of diagnostic molecular markers (such as IDH1/IDH2 gene mutations, ATRX gene mutation, 1p/19q codeletion, and TERT promoter mutation in adult tumors, and BRAF and H3FA3 aberrations in pediatric gliomas) and of predictive molecular markers (such as MGMT promoter methylation) [157]. The gene discussed is MGMT; the disease is central nervous system cancer.