Possible relationships of alcohol in membranes to cancer.

Ethanol can be used as a chemical tool to alter membrane fluidity or composition, or both, and to study the effects on induction, growth, spread, or treatment of cancers. Ethanol rapidly equilibrates with total body water and enters all cell membranes. Ethanol molecules are intercalated between the lipids of the bilayer membranes. This expands membranes and increases their fluidity, which in turn affects cell agglutination, phagocytosis, membrane transport, membrane enzyme activities, and many other membrane functions. After 3 to 5 days of continuous ethanol administration, the original membrane fluidity is restored by the incorporation of "stiffening" lipids, such as cholesterol, into the bilayer and by the increase of the chain length and saturation of fatty acids. The desired membrane effects (increased fluidity or altered membrane composition) can be obtained by adjusting time-dose relationships of ethanol administration. There may be an important role of moderate alcohol consumption in cancer biology that is not presently recognized by epidemiological studies because both cancers and moderate alcohol consumption are very prevalent in the general adult population. Moderate, social alcohol use could potentially either suppress or enhance the induction, growth, spread, or therapy of cancers. Such potential roles of alcohol in cancer biology could easily be tested in animals by incorporating the feeding of alcohol-containing diets into experiments that follow standard cancer protocols.