METTL1 and intrahepatic cholangiocarcinoma: The upregulated expression levels of METTL1 and/or WDR4 and their association with prognosis were observed in multiple types of cancer, including lung cancer [29], esophageal squamous cell carcinoma (ESCC) [30], intrahepatic cholangiocarcinoma (ICC) [27], hepatocellular carcinoma (HCC) [37], and glioma [38].