title: Increased concentrations of growth factors and activation of the EGFR system in breast cancer.
abstract: BACKGROUND
  In this study the total and phosphorylated amount of epidermal growth factor receptor 1 (EGFR) and 2 (HER2) were measured together with EGFR ligands in tissue samples of breast cancer patients in order to investigate interrelations and possible prognostic values.
  
  
  METHODS
  Samples of malignant and non-cancer autologous reference tissue were collected from 415 breast cancer patients. The tissue samples were cut and either paraffin-embedded or homogenized in a lysis buffer to extract the proteins. HER2 was measured using both immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) and ADVIA Centaur. Phosphorylated HER2 and EGFR (pHER2, pEGFR), total EGFR and the ligands: epidermal growth factor (EGF), transforming growth factor-α (TGFα), amphiregulin (AREG), heparin-binding EGF-like growth factor (HB-EGF), betacellulin (BTC) and epiregulin (EREG) were measured using the Luminex.
  
  
  RESULTS
  The HER2 positivity rate was determined to be 25.2% by the Centaur method vs. 15.8% by IHC and FISH. HER2, HB-EGF, TGFα and AREG were upregulated in cancer tissue as compared with autologous reference tissue while EGFR, pEGFR and EGF were downregulated (p<10-6). pEGFR in autologous reference tissue was negatively correlated to the number of positive lymph nodes and to the tumor size (p=0.0007 and p=0.001, respectively) and furthermore, decreased in the group of mastectomy operated patients as compared with the lumpectomy group (p<10-6). HB-EGF in cancer tissue was positively associated with high grade tumors (p<10-6) and pHER2, HB-EGF and BTC were associated with poor disease free survival (p=0.017, p=0.012 and p=0.0026, respectively).
  
  
  CONCLUSIONS
  Our study demonstrated a profound activation of the EGFR system. HB-EGF was increased by factor 10 in cancer tissue and related to the biological aggressiveness of the tumors, and pHER2, HB-EGF and BTC were associated with poor clinical outcome.
authors.affiliation: Department of Clinical Biochemistry, Vejle Hospital, Vejle, Denmark. Dorte.Aalund.Olsen@slb.regionsyddanmark.dk
authors.forename: Dorte Aa
authors.initials: DA
authors.lastname: Olsen
authors.forename: Troels
authors.initials: T
authors.lastname: Bechmann
authors.forename: Birthe
authors.initials: B
authors.lastname: Østergaard
authors.forename: Peter A
authors.initials: PA
authors.lastname: Wamberg
authors.forename: Erik H
authors.initials: EH
authors.lastname: Jakobsen
authors.forename: Ivan
authors.initials: I
authors.lastname: Brandslund
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000378:metabolism* / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008024:Ligands; D008875:Middle Aged; D010766:Phosphorylation; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*
chemical_list: D066246:ErbB Receptors; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D018719:Erb-b2 Receptor Tyrosine Kinases; C512478:EGFR protein, human; C508053:ERBB2 protein, human