To clarify whether PPM1G can endogenously affect TET1 in CCA cell lines, TFK‐1 and EGI‐1 were transfected with a control plasmid, 2, 4, and 6 μg of PPM1G‐HA plasmid, respectively, and changes in endogenous TET1 expression were subsequently detected. The gene discussed is TET1; the disease is cholangiocarcinoma.