GGCX and hepatocellular carcinoma: Later, the PXR-mediated effect of MK-4 was demonstrated using human hepatocellular carcinoma cells, which revealed that MK-4 suppresses cell proliferation and motility by acting both as a cofactor of GGCX and as a ligand to enhance PXR activation, thereby preventing the occurrence and recurrence of hepatocellular carcinoma [28].