IDH1 and neoplasm: Specifically, we observed a large subset of IDH mutant LGG G-CIMP-high tumor patients (37 of 53, 70%) that retained their normal-like epimethyl phenotype as a form of epigenetic memory when relapsed, but only a rare proportion of IDH mutant LGG G-CIMP-high tumor patients (9 of 53, 17%) underwent disease progression as G-CIMP-low epimethyl phenotype when relapsed for the first time.