To validate that the effects of METTL9-mediated tumor promotion mainly depended on SLC7A11, We overexpressed SLC7A11 in stably METTL9-knockdown HepG2 and PLC-8024 cells, and knockdown SLC7A11 in stably METTL9-overexpressing Huh7 cells respectively (Fig. 5E, F, Fig S4C). This evidence concerns the gene METTL9 and neoplasm.