[Alcohol and cancer]

Numerous studies have identified alcohol as the main risk factor for cancer of the upper GI tract such as pharynx, larynx and esophagus. Alcohol consumption is also associated with an enhanced risk for hepatocellular, breast and colorectal cancer. Animal experiments have demonstrated, that alcohol per se is not carcinogenic but rather exerts tumor-promoting and cocarcinogenic properties in animal models. These findings may be explained by recent experimental and epidemiological studies which have focused on the first metabolite acetaldehyde as the main tumorigenic substance of alcohol abuse. Other possible tumor promoting effects of alcohol are the existence of carcinogenic congeners in alcoholic beverages, an increased solubility of carcinogens by alcohol, a reduced intake and bioavailability of possible cancer protective substances, an inhibition of detoxification of carcinogenic compounds or increased activation of procarcinogens by cytochrome P450IIE1 which is induced by alcohol and a suppressed immune function. Alcohol also leads to a direct local mucosal damage, which results in a chronically increased cell division and thus an increased cancer risk.