Chronic , excessive alcohol consumption entails structural changes in the liver , brain and other organs , and is associated with an increased risk of developing certain types of cancer. Ethanol metabolism leads to the formation of acetaldehyde and acetic acid. Acetaldehyde adducts with DNA and proteins , reduces the efficiency of DNA repair systems and also reduces the level of glutathione , a peptide involved in detoxification . When ethanol metabolism by cytochromes and by alcohol dehydrogenase and xanthine oxidase as free radicals. Kokarcynogenne properties of ethanol are also associated with deficiencies of vitamins and micronutrients , such as vitamin A, folate , zinc , selenium , and with the possibility of induction of cytochrome P -450 2E1 , associated with an enhanced activation of various procarcinogens . The formation of tumors can be of particular mechanisms which characterize the upper gastrointestinal tract . In the case of the liver , these mechanisms can lead to chronic inflammation and cirrhosis , on a substrate which are often hepatocellular carcinoma.