Expression data from MCF7 tumor xenografts treated with either single agent BMS754807, or Tamoxifen or Letrozole alone; or Tamoxifen or Letrozole in combination with BMS754807 for 28 days

breast cancer. Combined IGF and estrogen-targeted therapy may improve the benefit of hormonal therapy alone. We employed a postmenopausal model of estrogen-dependent breast cancer in vitro and in vivo using the aromatase-expressing MCF-7/AC-1cells. Using this model, we investigated the anti-tumor effects of the dual IGF-1R/InsR tyrosine kinase inhibitor, BMS-754807 alone and in combination with letrozole or tamoxifen in vivo.

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