To determine the “driver” role of METTL14 and R298H mutations during CCA development, we first verified that there were no R298H mutations of METTL14 in CCA cell lines (RBE and HCCC9810) using sanger sequencing (Supplementary Fig. 3G), and then confirmed the transfection efficiency of lentiviral constructs expressing METTL14wt and METTL14R298H in RBE and HCCC9810 cell lines (Fig. 4D, Supplementary Figs. 3D, E, and 7C). The gene discussed is METTL14; the disease is cholangiocarcinoma.