Interestingly, when these HCC cell lines were treated with CPO, the IC50 value for CPO was inversely proportional to CD133 expression in the Huh6 (1.3 μM) > PLC/PRF/5 (1.2 μM) > Huh7 (413.8 nM) > Hep3B (464.8 nM) cells (Figure 1F). This evidence concerns the gene PROM1 and hepatocellular carcinoma.