Breast cancer is the most commonly occurring cancer among women. It is second to lung cancer as a cause of cancer death and is the first among cancers for causing early death. The risk of breast cancer development in women is one out of eight. Increased lifetime exposure to endogenous and exogenous estrogen has been implicated as a risk factor for breast cancer. Risk is increased for women with long cumulative exposure to estrogen, that is, for those experiencing early menarche, late menopause, late first full term pregnancy (FFTP), or no pregnancies. CYP1A1 is among the major enzymes participating in estrogen hydroxylation to hormonally inactive, water soluble metabolites, hydroxy estrogen (HE), which is an important mean of eliminating estrogen.