ROLE OF ETHANOL METABOLISM TO ACETALDEHYDE AND FREE RADICALS IN THE INCREASED RISK OF BREAST CANCER BY ALCOHOL-DRINKING

J.A. CASTRO; G.D. CASTRO

Washington DC

Congreso; 2008 Joint Scientific Meeting of the Research Society on Alcoholism and the International Society for Biomedical Research on Alcoholism; 2008

Research Society on Alcoholism (RSA) and the International Society for Biomedical Research on Alcoholism (ISBRA)

It is at present well established that alcohol consumption is associated with a modest, but significantly increased risk of breast cancer. The risk for breast cancer was significantly increased even with a moderate consumption of alcohol, irrespective of the types of alcohol beverages. Alcohol-induced risk of breast cancer was independent of other risk factors such as menopausal status, use of oral contraceptives, hormone replacement therapy, or genetic history of breast cancer. The precise mechanism for the increased risk of drinking alcoholic beverages in breast cancer promotion is still far from being established. But, some recent interesting studies, from others and by our laboratory, suggest that acetaldehyde produced elsewhere (e.g. in liver) and arriving at mammary tissue via blood or produced by metabolic transformation in the mammary tissue, could be a putative agent in the mutational event responsible for initiation step of the ethanol promoted breast cancer. Further, in additional studies we found that acetaldehyde in mammary tissue (produced in situ and transported via circulation) tends to accumulate to higher concentrations because of the low levels of aldehyde dehydrogenase activity in mammary tissue. The acetaldehyde accumulative process in mammary tissue increased with the dose of alcohol and lasted for a long period of time. This condition also decreases cell defenses against injury. In fact, repetitive administration for 28 days provided evidence to demonstrate the ability of alcohol to promote oxidative stress in mammary tissue. The increased susceptibility to oxidative stress was demonstrated even after a single high dose of ethanol to rats, which is equivalent to a typical binge-drinking situation. Therefore, acetaldehyde accumulation in breast tissue might potentially be a crucial event occurring after alcohol drinking, which might play a significant role in increasing risk of breast cancer.