METTL3 and intrahepatic cholangiocarcinoma: In the present study, we first found that knockdown of tri-methyltransferase decreased the enrichment of H3K4me3 in METTL3 and inhibited the mRNA expression of METTL3. In contrast, KDM5 inhibitors can increase the enrichment of H3K4me3 in METTL3 and increase METTL3 transcription, suggesting that H3K4me3 modification mediated METTL3 transcription in ICC.