In human hepatoma HepG2 cells, CAR induces cell apoptosis by selectively decreasing phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and P38 [32]; In human macrophage-like U937 cells, in response to lipopolysaccharide treatment, CAR activates peroxisome proliferator-activated receptors (PPAR alpha and gamma) and suppresses cyclooxygenase-2 (COX-2) mRNA and protein expression [33]. Here, MAPK3 is linked to hepatocellular carcinoma.