METTL1 and hepatocellular carcinoma: Other studies demonstrated that another component of the tRNA m7G methyltransferase complex, methyltransferase-like 1 (METTL1), was upregulated in some malignancies, such as hepatocellular carcinoma and lung adenocarcinoma, and was associated with poor patient prognosis and resistance to chemotherapy (22, 23).