The liver-selective hepatotoxin diethylnitrosamine (DEN) (Tolba et al., 2015) undergoes CYP2E1-mediated oxidation (Kang et al., 2007) to become a genotoxin (Bakiri and Wagner, 2013), leading to hepatocyte apoptosis and tissue damage that can progress to cirrhosis and HCC (Tolba et al., 2015). This evidence concerns the gene CYP2E1 and hepatocellular carcinoma.