Low dose estrogen supplementation reduces mortality of mice in estrogen-dependent human tumor xenograft model.

Breast cancer is one of the most frequent female cancers in the Western world. Perturbation of estrogen levels by hormone replacement therapy or pregnancy is associated with a variety of diseases, including breast cancer. Estrogen supplementation is required to establish appropriate animal models for estrogen-related diseases. In this report, we demonstrated that supplementation with high doses of 17beta-estradiol results in deaths in estrogen-dependent MCF-7 tumor xenograft model. Renal damage and bladder stone formation was implicated as a major cause of death. The mortality rate was significantly reduced when mice received a low dose of 17beta-estradiol. We also confirmed that low dose of 17beta-estradiol supplementation can support the growth of tumors in MCF-7 tumor xenograft model. These results suggest that low dose estrogen supplementation may be more appropriate in estrogen-dependent tumor xenograft models.