Epidemiological studies suggest that alcohol consumption increases the risk of developing
colorectal cancer. However, the data are confounded by numerous cosegregating variables. To cast further light on the relationships between alcohol intake and
colon cancer development, 21-day-old male F344/DuCrj rats were fed 200 ppm 2-amino-3,8-dimethylimidazo[4,5-f]
quinoxaline (MeIQx) in their diet for 8 weeks and doses of 0, 0.1, 0.3, 1, 3, 10 and 20% of
ethanol in their
drinking water ad libitum for 16 weeks thereafter. The rats were sacrificed after 24 weeks of experiment, and
aberrant crypt foci (ACF), surrogate lesions for
colon cancer, were examined under a light microscope at low magnification.
Ethanol was found not to affect the ACF formation at any dose compared with the initiated-controls. Furthermore,
ethanol did not alter colon epithelial cell proliferation. These data, obtained by analysis of a
colon cancer surrogate marker lesion, indicate that
ethanol lacks promotion activity for MeIQx-initiated rat colon
carcinogenesis.