IDH2 and acute myeloid leukemia: Wang et al. reported a screening of serum 2-HG levels in a large group of Chinese AML patients and showed that 17% of these patients displayed 2-HG levels above the cutoff value; 87% of AML cases with very high serum 2-HG levels displayed IDH1 or IDH2 mutations; 29% of patients with moderately increased serum 2-HG levels possessed IDH mutations, thus suggesting that events other than IDH mutations exist, causing an increased 2-HG production [130].