title: ErbB 1-4 expression alterations in primary colorectal cancers and their corresponding metastases.
abstract: BACKGROUND
  EGFR (epidermal growth factor receptor) targeted therapies are important new tools in colorectal cancer treatment. EGFR analysis of the primary tumour was previously recommended to identify patients who will benefit from the EGFR targeted therapy. Previous studies have displayed diverging results regarding the expression of EGFR in the primary tumour compared to the metastases. The present study was performed to investigate whether EGFR and ErbB2-4 expression differed between 64 primary tumours and their corresponding metastases.
  
  
  METHODS
  EGFR and ErbB2-4 expression were analysed in the primary tumour and in the corresponding metastases using immunohistochemistry (IHC).
  
  
  RESULTS
  In 49/64 samples (76%), the primary tumours were EGFR positive; in 33% (16/49) of EGFR positive samples, the tumours lost the EGFR expression in the metastasis compared to the primary tumour. From the primary tumours, 15/64 (23%) were negative and 5 of these (33%) developed EGFR expression in the metastasis. ErbB2, ErbB3, and ErbB4 expression was evident in 54%, 67%, and 81%, respectively. There was no significant difference between ErbB2, ErbB3, and ErbB4 expression in primary tumours and metastases. The co-expression of the ErbB family members was also analysed, with a significant increase of ErbB3/ErbB4 co-expression in late stage tumours.
  
  
  CONCLUSIONS
  The EGFR expression was lost in 33% of metastasising primary colorectal cancer tumours, a finding that agrees with at least one previous study. Thus, the present results clearly implicate the need for EGFR analysis of both the primary tumour and metastases to accurately determine EGFR status when considering the use of EGFR targeted therapies.
authors.affiliation: Department of Radiation sciences, Oncology, Umeå University Hospital, Umeå University SE-90187 Umeå, Sweden. ingrid.ljuslinder@onkologi.umu.se
authors.forename: Ingrid
authors.initials: I
authors.lastname: Ljuslinder
authors.forename: Beatrice
authors.initials: B
authors.lastname: Malmer
authors.forename: Martin
authors.initials: M
authors.lastname: Isaksson-Mettävainio
authors.forename: Ake
authors.initials: A
authors.lastname: Oberg
authors.forename: Roger
authors.initials: R
authors.lastname: Henriksson
authors.forename: Roger
authors.initials: R
authors.lastname: Stenling
authors.forename: Richard
authors.initials: R
authors.lastname: Palmqvist
mesh_terms: D015179:Colorectal Neoplasms / Q000378:metabolism* / Q000473:pathology; D066246:ErbB Receptors / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009362:Neoplasm Metastasis; D020794:Receptor Protein-Tyrosine Kinases / Q000378:metabolism*
chemical_list: D066246:ErbB Receptors; D020794:Receptor Protein-Tyrosine Kinases