The Editor-in-Chief, in agreement with the authors, has decided to retract this article.

Upon investigation carried out according to the Committee on Publication Ethics guidelines, it has been found that substantial parts of the paper have been duplicated, mainly from the following articles:

1. Crosstalk of TGF-β and Estrogen Receptor Signaling in Breast Cancer, Band AM, Laiho M (2011) J Mammary Gland Biol Neoplasia 16:109–115.

2. Molecular mechanisms of endocrine resistance and their implication in the therapy of breast cancer, Zilli M, Grassadonia A, Tinari N, Di Giacobbe A, Gildetti S, Giampietro S, Natoli C, Iacobelli S, on behalf of Consorzio Interuniversitario Nazionale per la Bio-Oncologia (CINBO) (2009) BBA Reviews on Cancer, 1795:62–81

3. Crosstalk Between IGF1R and Estrogen Receptor Signaling in Breast Cancer, Fagan DH, Yee D (2008) J Mammary Gland Biol Neoplasia 13:423-429

4. The silent estrogen receptor. Can we make it speak? Billam M, Witt AE, Davidson NE (2009) Cancer Biology & Therapy 8:6, 485-496

5. Steering Estrogen Signals From the Plasma membrane to the Nucleus: Two Sides of the Coin, Manavathi B, Kumar R (2006) Journal of Cellular Physiology 207:594-604

6. Role of Estrogen Receptor Signaling in Breast Cancer Metastasis, Roy SS, Vadlamudi RK (2012) International Journal of Breast Cancer, doi:10.1155/2012/654698