OBI1 and hepatocellular carcinoma: Consistent with this hypothesis, the 5‐methylcytosine (5mc) level in RNF219 promoter in high bone‐metastatic HCCLM3‐BM4 cells and HCC‐BM tissues was significantly less than that in HCCLM3‐P cells and non‐BM HCC tissues (Figure S8C,D, Supporting Information).