The mechanism behind this is thought to be vitamin E activation of a nuclear pregnane X receptor (PXR) driven chloramphenicol acetyltransferase (CAT) reporter in HepG2 cells, a human hepatoma cell line that is typically used in drug metabolism and hepatotoxicity studies which can mediate and induce CYP functions (Brigelius-Flohé, 2007). Here, NR1I2 is linked to hepatocellular carcinoma.