IDH1 and glioma: For the target condition, 22 studies focused on IDH mutation status, 6 on 1p/19q codeletion status, 11 on MGMT promoter methylation status, 3 on TP53 mutation status, 1 on the PTEN gene mutation, 2 on ATRX gene mutation status, 3 on the TERT promoter mutation, and 20 on the differentiation between different subtypes of glioma.