TET3 and intrahepatic cholangiocarcinoma: Of note, mutations of these DNA methylation-modifying genes are relatively rare (Figure 2A), including DNMT1 (5%), DNMT3A (2.7%), DNMT3B (4%), TET1 (4%), TET2 (2%), and TET3 (2.4%); however, DNMT3A and TET2 are relatively high at the protein level but vary with different ages, while the levels of DNMT1, DNMT3B, and TET3 are moderate or relatively low (Figure 2B); and the expression of these genes correlates, either positively (for DNMT3A, DNMT3B, and TET3) or negatively (for DNMT1, TET1, and TET2), with the overall survival of ICC patients (Figure 2C).