IDH2 and astrocytoma (excluding glioblastoma): Additionally, recent studies uncovered somatic mutations in the two IDH isoforms, IDH1 and IDH2, which occur at high frequencies in cancers, including gliomas, astrocytomas, chondromas and acute myeloid leukemia (AML) (Parsons et al., 2008; Ward et al., 2012; Ward et al., 2010; Yan et al., 2009; Zhao et al., 2009).