5hmC levels are decreased in TET2 and IDH mutated patients. (A) Plasma 2HG levels measured by LC-MS/MS were up to 150 times higher in patients with IDH mutations compared with IDH wild-type patients. (B) Small differences in 5mC values were present between AML patients. Patients with IDH mutations showed higher 5mC levels than TET2 mutated and TET2/IDH wild-type patients. (C) Patients with TET2 or IDH1/2 mutations showed significantly lower 5hmC levels than TET2/IDH wild-type patients. (D) Patients with 2 affected TET2 alleles showed lower 5hmC values than patients with only 1 affected allele. All types of IDH mutations led to decreased 5hmC levels. The 4 patients with an IDH2 R172 mutation had slightly lower 5hmC values than most patients with an IDH1 R132 or IDH2 R140 mutation. (E) DNMT3A mutations frequently co-occurred with TET2 or IDH mutations. DNMT3A mutations did not significantly affect global 5mC levels. (F) Mutant DNMT3A also did not strongly affect 5hmC values, but the levels were influenced by the presence or absence of accompanying TET2 or IDH mutations. Mut, mutated; wt, wild type. Symbols indicate unpaired t test (*), Mann-Whitney U test (†), 1-way analysis of variance (‡), and Kruskal Wallis test (§).