WDR4 and hepatocellular carcinoma: Recently, some studies have shown that some of the m7G-related genes like methyltransferase-like protein-1 (METTL1) and WD repeat domain 4 (WDR4) are involved in the proliferation, migration, and invasion of HCC through m7G tRNA modification (Chen et al., 2021; Xia et al., 2021).