title: HER2 Equivocal Status in Early Breast Cancer Is Not Associated with Higher Risk of Recurrence.
abstract: OBJECTIVE
  The primary aim of the study was to assess the association between risk of recurrence and HER2 equivocal gene status through immunohistochemistry in patients with early breast cancer.
  
  
  METHODS
  We retrospectively analyzed clinical and pathological data of 455 consecutive patients with early breast cancer (BC) who were HER2(+) and had a HER2/CEP17 ratio <2.0, who underwent surgery at the European Institute of Oncology after 2007. The role of HER2/CEP17 ratio on recurrence-free survival was assessed with univariate and multivariate Cox regression models.
  
  
  RESULTS
  We found no significant association between risk of recurrence and HER2 equivocal testing in patients with early breast cancer. In subgroup analysis, a significant interaction between HER2/CEP17 ratio and nodal involvement was observed (p=0.02).
  
  
  CONCLUSIONS
  Patients with HER2 equivocal status have no significantly higher risk of recurrence.
authors.affiliation: Division of Experimental Therapeutics, University of Milan-Bicocca, Milan, Italy.
authors.forename: Carmen
authors.initials: C
authors.lastname: Criscitiello
authors.affiliation: Division of Epidemiology and Biostatistics, University of Milan-Bicocca, Milan, Italy Department of Statistics and Quantitative Methods, University of Milan-Bicocca, Milan, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Bagnardi
authors.affiliation: Department of Pathology, School of Medicine, University of Milan, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Viale
authors.affiliation: Division of Epidemiology and Biostatistics, University of Milan-Bicocca, Milan, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Disalvatore
authors.affiliation: Division of Experimental Therapeutics, University of Milan-Bicocca, Milan, Italy.
authors.forename: Nicole
authors.initials: N
authors.lastname: Rotmensz
authors.affiliation: Division of Experimental Therapeutics, University of Milan-Bicocca, Milan, Italy.
authors.forename: Angela
authors.initials: A
authors.lastname: Esposito
authors.affiliation: Breast Health Program, European Institute of Oncology, Milan, Italy.
authors.forename: Aron
authors.initials: A
authors.lastname: Goldhirsch
authors.affiliation: Division of Experimental Therapeutics, University of Milan-Bicocca, Milan, Italy giuseppe.curigliano@ieo.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Curigliano
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000378:metabolism* / Q000401:mortality / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D015870:Gene Expression; D006801:Humans; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000378:metabolism* / Q000401:mortality; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Breast cancer; HER2 amplification; equivocal HER2 status; heterogeneity