title: Expression of the HER1-4 family of receptor tyrosine kinases in breast cancer.
abstract: EGFr/HER1 and c-erbB-2/HER2 expression are associated with poor prognosis in breast cancer. The type I receptor tyrosine kinase (RTK) family to which they belong has four members (HER1-4). In this study, expression of HER1-4 and oestrogen receptor (ER) expression were determined by immunohistochemistry in 220 breast carcinomas. Elevated expression of HER1 was observed in 16.4%, HER2 in 22.8%, HER3 in 17.5%, and HER4 in 11.9% of these tumours. Patients whose tumours overexpressed HER1, 2 or 3 had reduced survival (p= <0.001), whereas those whose tumours overexpressed HER4 had increased survival (p=0.013); 38.6% of cases overexpressed one or more of HER1, 2 or 3. HER4 was rarely overexpressed with other HERs (1.4% of cases). Cox's multiple regression analysis demonstrated that overexpression of HER1/2/3, HER4, and standard prognostic indicators independently affected survival. HER1-3 expression was related to ER negativity (p<0.0001, chi2). Patients with ER-positive, HER1-3-positive tumours had a significantly poorer survival (p<0.001) than those with ER-positive/HER-negative or HER4-positive tumours. Expression of HER RTKs displays complex interactions between different family members. There is a strong interaction, in terms of survival, between HER expression and ER expression. The development of HER-targeted agents (eg Herceptin, Iressa), and agents targeted at the downstream signalling pathways, therefore provides new possibilities in the treatment of breast cancer.
authors.affiliation: University Department of Surgery, Glasgow Royal Infirmary, Glasgow G31 2ER, UK.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Witton
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Reeves
authors.forename: James J
authors.initials: JJ
authors.lastname: Going
authors.forename: Timothy G
authors.initials: TG
authors.lastname: Cooke
authors.forename: John M S
authors.initials: JM
authors.lastname: Bartlett
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality; D066246:ErbB Receptors / Q000235:genetics*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D018815:Genes, erbB / Q000235:genetics*; D018773:Genes, erbB-1 / Q000235:genetics; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D011379:Prognosis; D011505:Protein-Tyrosine Kinases / Q000235:genetics*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D020893:Receptor, ErbB-3 / Q000235:genetics; D066247:Receptor, ErbB-4; D011960:Receptors, Estrogen / Q000032:analysis
chemical_list: D066246:ErbB Receptors; D011505:Protein-Tyrosine Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; D011960:Receptors, Estrogen; C587689:ERBB4 protein, human