Alcohol's Promotion of Gastrointestinal Carcinogenesis
This chapter discusses the effects of ethanol and their underlying mechanisms with a special focus on ethanol promotion/progression effects in the light of our recent findings. Alcohol is a major cancer risk factor. The association is particularly strong with cancers of the upper aerodigestive tract – 75% of esophageal cancers and 50% of oral cavity cancers in the US are attributed to alcohol consumption. Ethanol may influence the preinitiation stage because it is an effective inducer of the cytochrome P-450 microsomal enzymes that are involved in converting procarcinogens into their DNA reactive electrophilic intermediates9 that are mutagenic. The results of ethanol effect on promotion of colorectal carcinogenesis are less clear. An increase in lipid peroxidation with tumor promotion occurring with ethanol metabolism may be followed by a subsequent decline when tumors appear as shown by us in dimethylbenzanthracene-induced oral carcinogenesis in hamsters.