Aside from the publication of (Chen et al., 2011), little information is available in the literature on the topic of alcohol drinking pattern and breast cancer risk. One important reason for focusing on this issue is that drinking pattern strongly influences the blood alcohol concentration (BAC). The BAC in turn, determines the biochemical changes that take place in the human body after alcohol drinking. Specifically, the BAC produced in a woman after a single drink of alcohol is approximately 10 mM, which is above the ethanol Km for the alcohol dehydrogenases expressed in the breast (ADH1B and ADH1C). The ethanol-inducible CYP2E1 expressed in human breast becomes significant for ethanol metabolism at higher BAC > 20 mM (Salaspuro and Lieber, 1978). BACs in this range would require consuming multiple drinks in a given setting. As noted above, alcohol metabolism by CYP2E1 leads to the formation of mutagenic DNA adducts (Millonig et al., 2011). Based on these considerations, a plausible hypothesis is that alcohol-related breast cancer risk is correlated with the amount of time when a woman has BACs at a level
