title: The potential role of estrogen receptors and the SRC family as targets for the treatment of breast cancer.
abstract: BACKGROUND
  Breast cancer has a number of subtypes, the main ones are estrogen-receptor (ER)-positive, luminal type A and B. Treatment selection, with respect to hormonal therapy, is based upon ER expression. Whilst for ER-positive cancers, endocrine therapy is highly successful in the adjuvant setting, a significant proportion of cancers exhibit hormone resistance, often associated with altered growth factor receptor or ER signalling. Modulation of steroid receptor function by receptor co-activators or repressors is a potential mechanism of resistance. The p160 or SRC proto-oncogene family of co-activators are important in breast cancer response to endocrine therapy and can act as a paradigm of co-activator function.
  
  
  OBJECTIVE
  This review focuses on the role of ER and ER co-activators in breast cancer and current approaches to targeting SRC co-factors for treatment of hormone-receptor-positive breast cancer.
  
  
  CONCLUSIONS
  There is a drive to selectively apply aromatase inhibitors on the basis of either risk or biological evidence of resistance to tamoxifen treatment. Both strategies may yield improved treatment to benefit ratios.
authors.affiliation: University of Edinburgh, Edinburgh Cancer Research Centre, Crewe Road South, Edinburgh EH42XR, UK.
authors.forename: Melanie
authors.initials: M
authors.lastname: Spears
authors.forename: John
authors.initials: J
authors.lastname: Bartlett
mesh_terms: D001943:Breast Neoplasms / Q000188:drug therapy* / Q000201:enzymology / Q000378:metabolism; D020847:Estrogen Receptor Modulators / Q000627:therapeutic use; D047628:Estrogen Receptor alpha / Q000187:drug effects* / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D008024:Ligands; D000090063:Proto-Oncogene Mas; D015398:Signal Transduction; D019061:src-Family Kinases / Q000187:drug effects* / Q000378:metabolism
chemical_list: D020847:Estrogen Receptor Modulators; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D008024:Ligands; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D019061:src-Family Kinases