To examine the cellular functions of BMI1 in HCC tumorigenesis, we genetically modified BMI1 expression in the rat LPC line WBF344 and human HCC cell lines (i.e., PLC with low endogenous BMI1 level and MHCC97H with high endogenous BMI1) (Fig. 2a, b and Supplementary Fig. 2a). Here, BMI1 is linked to hepatocellular carcinoma.