TET1 and hepatocellular carcinoma: Previous studies revealed that among the three ten-eleven translocation (TET) genes, which encode the key dioxygenases that oxidize 5-position of cytosine (5-mC) into 5-hydroxymethylcytosine (5hmC), TET1 and TET2 have frequently been shown to exhibit downregulated expression in HCC tissue [17].