XPO1 and hepatocellular carcinoma: Treatment of the rat HCC JM1 cells with sodium butyrate did not affect the total level of CRM1 protein (Figure 3, Panel D), but markedly reduced the level of CRM1 protein in the cytoplasm and increased its level in the nuclei in rat HCC JM1 and human HCC PLC/PRF/5 p53-mutant cells (Figure 3, Panels E and F).