TET1 and cancer: It enhances the enzymatic activity of TET1 by increasing the activity of Fe(II) 2-oxoglutarate dioxygenase within the catalytic domain of TET1 and converting 5mC to 5hmC.45 Although this induces global demethylation, analysis of 5mC and 5hmC enrichment and mtDNA copy number during 28 days of differentiation of cancer cells demonstrates reversible changes that are indicative of the ‘rebound effect'.30 Moreover, increased expression of early neural markers suggests that these cells failed to fully differentiate into astrocytes.