title: [Clinical usefulness of circulating ECD/HER-2 measurement for breast cancer patients' management].
abstract: BACKGROUND
  About 15 to 20% of breast cancer cases overexpress human epidermal growth factor receptor-2 (HER-2). This overexpression is associated with poor clinical prognosis but therapeutic success of trastuzumab or lapatinib. HER-2 extracellular domain (ECD) undergoes a proteolytic cleavage and is shed into biologic fluid as a circulating antigen called ECD/HER-2, which can be detected by immunochemical assays.
  
  
  OBJECTIVE
  The aim of our review was to determine the clinical usefulness of ECD/HER-2 measurement in the management of breast cancer patients.
  
  
  METHODS
  A Pubmed search for publications in English or French was carried out until March 31, 2010 (69 original articles and 8 reviews).
  
  
  RESULTS
  The measurement of ECD/HER-2 concentration does not exempt from the pathological determination of HER-2 expression in tumors; some HER-2 negative tumors are associated with high levels of ECD/HER-2, on the other hand, some HER-2 positive tumors present low levels of ECD/HER-2. The concentration of ECD/HER-2 is correlated to disease progression, since 10% of loco-regional breast cancers and more than a third of metastatic breast cancers have high levels of ECD/HER-2. The elevation of ECD/HER-2 levels generally occurs several months before the diagnosis of symptomatic metastases. The relevance of ECD/HER-2 measurements during chemotherapy, hormone therapy and trastuzumab treatment remains uncertain. Similarly, it is not commonly agreed that high levels of ECD/HER-2 before any treatment in the case of an early breast cancer, is an independent prognostic factor.
  
  
  CONCLUSIONS
  A close analysis of a variety of pathological, biochemical, clinical and methodological data may explain these discrepancies.
  
  
  CONCLUSIONS
  New prospective studies using immunochemical measurements of ECD/HER-2 (with a consensual threshold) and based on both detailed pathological analyses and a comprehensive collection of clinical data are still required to establish the clinical usefulness of circulating ECD/HER-2 measurement for breast cancer patients' management.
authors.affiliation: CHRU de Strasbourg, pôle de gynécologie-obstétrique, unité de sénologie, avenue Molière, 67200 Strasbourg cedex, France. Carole.Mathelin@chru-strasbourg.fr
authors.forename: Carole
authors.initials: C
authors.lastname: Mathelin
authors.forename: Sabrina
authors.initials: S
authors.lastname: Croce
authors.forename: Sébastien
authors.initials: S
authors.lastname: Rault
authors.forename: Mouslim
authors.initials: M
authors.lastname: Gharbi
authors.forename: Francoise
authors.initials: F
authors.lastname: Eichler
authors.forename: Béatrice
authors.initials: B
authors.lastname: Gairard
authors.forename: Geneviève
authors.initials: G
authors.lastname: Coumaros
authors.forename: Christian
authors.initials: C
authors.lastname: Koehl
mesh_terms: D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000097:blood*; D005260:Female; D006801:Humans; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000097:blood*
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human