It has also been suggested that PXR and CAR play a role in the regulation of BA synthesis, since PXR has been described as a FXRα target gene, and its ligand activation directly regulates SHP expression in the HepG2 human liver cancer cell line and indirectly reduces the expression of Cyp7a1 in mice [36,50,51]. This evidence concerns the gene NR1I2 and liver cancer.