Alcohol and pancreatic cancer.

Findings obtained from numerous prospective cohort and case-control studies on alcohol consumption and pancreatic cancer risk have been inconsistent, with many confounding variables present in various investigations. However, heavy alcohol consumption has been known to be a major cause of chronic pancreatitis and a risk factor for type 2 diabetes mellitus, both of which are linked to pancreatic cancer. It has been established that an extensive normal interaction exists between the exocrine and endocrine pancreas, as well as in inflammatory processes and carcinogenesis. Alcohol and its metabolites (acetaldehyde and fatty acid ethyl esters) can alter metabolic pathways involved in the inflammatory response and carcinogenesis, and they are mediated by one or more of the following mechanisms: (1) premature activation of zymogens; (2) induction of the inflammatory response through activation of nuclear transcription factors, including nuclear factor-kappa and activation protein 1; (3) increased production of reactive oxygen species, resulting in oxidative DNA damage and altered effect of dietary antioxidants; (4) activation of pancreatic stellate cells, which leads to fibrosis; (5) gene mutation in enzymes related to cytochrome P450, glutathione S-transferase, aldehyde dehydrogenase, cationic trypsinogen, and pancreatic secretory trypsin inhibitor; (6) synergistic effects of ethanol and tobacco carcinogen on NNK [nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone] metabolism; and (7) dysregulation of proliferation and apoptosis. These various metabolic effects of alcohol can lead to or interact with other risk factors (genetic, dietary, environmental, and lifestyle factors) that result in acute and chronic pancreatitis and diabetes mellitus and, ultimately, affect the multistep process of carcinogenesis toward the development of pancreatic cancer.