title: EpCAM expression varies significantly and is differentially associated with prognosis in the luminal B HER2(+), basal-like, and HER2 intrinsic subtypes of breast cancer.
abstract: BACKGROUND
  Epithelial cell adhesion molecule (EpCAM) is frequently expressed in breast cancer, and its expression has been associated with poor prognosis. Breast cancer can be subdivided into intrinsic subtypes, differing in prognosis and response to therapy.
  
  
  METHODS
  To investigate the association between EpCAM expression and prognosis in the intrinsic subtypes of breast cancer, we performed immunohistochemical studies on a tissue microarray encompassing a total of 1365 breast cancers with detailed clinicopathological annotation and outcomes data.
  
  
  RESULTS
  We observed EpCAM expression in 660 out of 1365 (48%) cases. EpCAM expression varied significantly in the different intrinsic subtypes. In univariate analyses of all cases, EpCAM expression was associated with a significantly worse overall survival. In the intrinsic subtypes, EpCAM expression was associated with an unfavourable prognosis in the basal-like and luminal B HER2(+) subtypes but associated with a favourable prognosis in the HER2 subtype. Consistently, specific ablation of EpCAM resulted in increased cell viability in the breast cancer cell line SKBR3 (ER(-), PR(-), and HER2(+)) but decreased viability in the breast cancer cell line MDA-MB-231 (ER(-), PR(-), and HER2(-) ).
  
  
  CONCLUSIONS
  The differential association of EpCAM expression with prognosis in intrinsic subtypes has important implications for the development of EpCAM-targeted therapies in breast cancer.
authors.affiliation: Department of Surgery, University Hospital Basel, Spitalstrasse 21, Basel 4031, Switzerland.
authors.forename: S D
authors.initials: SD
authors.lastname: Soysal
authors.forename: S
authors.initials: S
authors.lastname: Muenst
authors.forename: T
authors.initials: T
authors.lastname: Barbie
authors.forename: T
authors.initials: T
authors.lastname: Fleming
authors.forename: F
authors.initials: F
authors.lastname: Gao
authors.forename: G
authors.initials: G
authors.lastname: Spizzo
authors.forename: D
authors.initials: D
authors.lastname: Oertli
authors.forename: C T
authors.initials: CT
authors.lastname: Viehl
authors.forename: E C
authors.initials: EC
authors.lastname: Obermann
authors.forename: W E
authors.initials: WE
authors.lastname: Gillanders
mesh_terms: D000951:Antigens, Neoplasm / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D048708:Cell Growth Processes / Q000502:physiology; D045744:Cell Line, Tumor; D000071858:Epithelial Cell Adhesion Molecule; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000378:metabolism*; D046888:Tissue Array Analysis
chemical_list: D000951:Antigens, Neoplasm; D015815:Cell Adhesion Molecules; D000071858:Epithelial Cell Adhesion Molecule; D018719:Erb-b2 Receptor Tyrosine Kinases; C499379:EPCAM protein, human