METTL14 and cancer: In liver cancer research, it was found that methyltransferase METTL14 has a dual effect of promoting cancer cell proliferation and differentiation and inhibiting cancer cell metastasis (Ma et al., 2017; Chen et al., 2018); Overexpression of METTL5 promotes the growth, proliferation, migration, and invasion of liver cancer, knockdown of METTL5 promotes cell apoptosis, and inhibits the growth, proliferation, migration, and invasion of liver cancer (Peng et al., 2022).