METTL3 and hepatocellular carcinoma: One study used a lentivirus-based clustered regularly interspaced short palindromic repeat (CRISPR) gene editing system (lentiCRISPR v2) to knock out METTL3 in the HCC cell line Huh-7, and subsequently injected the knocked-out METTL3 cell line in situ into the left liver lobe of nude mice using in situ transplantation experiments, and found that knocking out METTL3 significantly inhibited the growth of HCC tumors in situ in the liver of nude mice (Chen et al., 2018).