In the case of liver cancer, for example, both obesity and alcohol consumption could lead to oxidative stress and liver injury via multiple metabolic pathways, including cytochrome P450 2E1 induction, free radical generation, lipid peroxidation, TNF-α production and increased transcription of pro-inflammatory mediators(46–48). The gene discussed is CYP2E1; the disease is obesity due to melanocortin 4 receptor deficiency.