Estrogen exposure is a major risk factor for breast cancer. Increased estrogen responsiveness of breast epithelium may enhance this effect. Surgical or medical castration and antiestrogenic treatment with tamoxifen are common endocrine treatments for premenopausal women with breast cancer.However, tamoxifen therapy induces high levels of plasma estradiol, with unknown long-term effects. In this study, we investigated the effect of combining the luteinizing hormone-releasing hormone agonist with tamoxifen and measuring estradiol level . method : Are taking random samples of breast cancer patients under treatment of patients attending the Institute of Atomic Radiation in Baghdad , and specifically who use Tamoxifen ( 20 mg/day) . 100 samples and 30 sample as a control there age ( 20 -80). Approximately 3ml of blood are collected from each women using standard procedures. And then measuring the level of estradiol E2 hormone ,Measurement of the liver enzymes ( GOT,GPT,ALP,LDH and GGT ) and billirubin for study the liver health results : combined treatment with tamoxifen and