title: EpCAM expression in primary tumour tissues and metastases: an immunohistochemical analysis.
abstract: OBJECTIVE
  Epithelial cell adhesion molecule (EpCAM) is a cell surface protein with oncogenic features that is expressed on healthy human epithelia and corresponding malignant tumours. EpCAM expression frequently correlates with more aggressive tumour behaviour and new EpCAM-specific therapeutic agents have recently been approved for clinical use in patients with cancer. However, no consensus exists on how and when to evaluate EpCAM expression in patients with cancer.
  
  
  METHODS
  EpCAM expression was assessed by a well-established immunohistochemical staining protocol in 2291 primary tumour tissues and in 108 metastases using the EpCAM-specific antibody clone VU1D9. A total immunostaining score was calculated as the product of a proportion score and an intensity score. Four expression subgroups (no, weak, moderate and intense) were defined. As described previously, the term 'EpCAM overexpression' was reserved for tissues showing a total immunostaining score >4.
  
  
  RESULTS
  EpCAM was highly expressed in most tumours of gastrointestinal origin and in some carcinomas of the genitourinary tract. However, hepatocellular carcinomas, clear cell renal cell cancer, urothelial cancer and squamous cell cancers were frequently EpCAM negative. EpCAM expression in breast cancer depended on the histological subtype; lobular histology usually showed no or weak expression. Most metastases were EpCAM positive and they frequently reflected the expression phenotype of the primary tumour.
  
  
  CONCLUSIONS
  EpCAM expression was detected on adenocarcinomas of various primary sites. If EpCAM-specific antibodies are intended to be used in patients with cancer, we recommend prior immunohistochemical evaluation of EpCAM expression, particularly in patients with renal cell cancer, hepatocellular carcinoma, urothelial carcinoma, breast cancer and squamous cell carcinomas.
authors.affiliation: Laboratory for Experimental Oncology (Tyrolean Cancer Research Institute), Innsbruck Medical University, Innsbruck, Austria. gilbert.spizzo@i-med.ac.at
authors.forename: Gilbert
authors.initials: G
authors.lastname: Spizzo
authors.forename: Dominic
authors.initials: D
authors.lastname: Fong
authors.forename: Martin
authors.initials: M
authors.lastname: Wurm
authors.forename: Christian
authors.initials: C
authors.lastname: Ensinger
authors.forename: Peter
authors.initials: P
authors.lastname: Obrist
authors.forename: Carina
authors.initials: C
authors.lastname: Hofer
authors.forename: Guido
authors.initials: G
authors.lastname: Mazzoleni
authors.forename: Guenther
authors.initials: G
authors.lastname: Gastl
authors.forename: Philip
authors.initials: P
authors.lastname: Went
mesh_terms: D000951:Antigens, Neoplasm / Q000378:metabolism*; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001943:Breast Neoplasms / Q000378:metabolism; D002277:Carcinoma / Q000145:classification / Q000378:metabolism*; D015815:Cell Adhesion Molecules / Q000378:metabolism*; D045744:Cell Line, Tumor; D004067:Digestive System Neoplasms / Q000378:metabolism; D000071858:Epithelial Cell Adhesion Molecule; D005260:Female; D005770:Gastrointestinal Neoplasms / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D009362:Neoplasm Metastasis; D009369:Neoplasms / Q000145:classification / Q000378:metabolism*; D012142:Respiratory Tract Neoplasms / Q000378:metabolism; D014565:Urogenital Neoplasms / Q000378:metabolism
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule