This is suggesting that alcohol in increases aromatase and thereby the oestrogen estradiol. Higher estradiol is a BC risk factor.
Complex stuff and acknowledgement of difficulties in testing but thought provoking.
RB
http://cebp.aacrjournals.org/cgi/reprint/7/3/189.pdf
PS please excuse typo in heading - I cannot change it - rushing and burning the midnight oil.