What clinicians need to know about antioestrogen resistance in breast cancer therapy

Eur J Cancer. 2006 Nov;42(16):2692-705. doi: 10.1016/j.ejca.2006.06.022. Epub 2006 Sep 11.


Tamoxifen is the drug most used for early breast cancer treatment in oestrogen receptor (ER) positive patients. Unfortunately, despite high ER tumour levels in a tumour, resistance to endocrine therapy, either de novo or acquired after prolonged treatment, can occur. In this review, we will try to summarise the postulated mechanisms of hormonal-resistance, namely, the role of co-regulators and the crosstalk between the HER-2, IGF-IR, Cox-2 and ER pathways. Other predictive markers of tamoxifen-resistance/response, such as cyclin E and UPA/PAI-1, are also discussed.

Publication types

  • Review

MeSH terms

  • Antineoplastic Agents, Hormonal / therapeutic use
  • Biomarkers, Tumor / analysis
  • Breast Neoplasms / drug therapy*
  • Breast Neoplasms / metabolism
  • Cyclin E / metabolism
  • Drug Resistance, Neoplasm*
  • Estrogen Antagonists / therapeutic use*
  • Female
  • Humans
  • Oncogene Proteins v-erbB / metabolism
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • Receptors, Estrogen / metabolism
  • Receptors, Progesterone / metabolism
  • Somatomedins / metabolism
  • Urokinase-Type Plasminogen Activator / metabolism


  • Antineoplastic Agents, Hormonal
  • Biomarkers, Tumor
  • Cyclin E
  • Estrogen Antagonists
  • Oncogene Proteins v-erbB
  • Proto-Oncogene Proteins c-bcl-2
  • Receptors, Estrogen
  • Receptors, Progesterone
  • Somatomedins
  • Urokinase-Type Plasminogen Activator