Other possible mechanisms include increased estrogen concentration (mainly for breast cancers), increased levels of plasma insulin-like growth factors produced by the liver following alcohol consumption, alcohol acting as a solvent for tobacco carcinogens, alcohol-related lesions that favor the absorption of carcinogens in the aerodigestive tract epithelium, the production of reactive oxygen and nitrogen species, changes in folate metabolism, and changes in DNA repair42,43. This evidence concerns the gene INS and breast carcinoma.