METTL1 and cancer: m7G at tRNA catalyzed by METTL1/WDR4 was found to stabilize tRNA and increase tRNAs expression, which resulted in enhanced oncogenic mRNA translation and tumor progression in a series of cancers, such as intrahepatic cholangiocarcinoma, glioblastoma multiforme, hepatocellular carcinoma, lung cancer and bladder cancer [23–27].