title: Gene status in HER2 equivocal breast carcinomas: impact of distinct recommendations and contribution of a polymerase chain reaction-based method.
abstract: BACKGROUND
  The primary objectives of this study on carcinomas with equivocal HER2 expression were to assess the impact of distinct recommendations with regard to identifying patients eligible for anti-HER2 agents by fluorescence in situ hybridization (FISH) and to elucidate whether multiplex ligation-dependent probe amplification (MLPA) may be of support in assessing HER2 gene status.
  
  
  METHODS
  A cohort of 957 immunohistochemistry-evaluated HER2-equivocal cases was analyzed by dual-color FISH. The results were assessed according to U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) guidelines and American Society of Clinical Oncology (ASCO) and College of American Pathologists (CAP) 2007 and 2013 guidelines for dual- and single-signal in situ hybridization (ISH) assays. A subgroup of 112 cases was subjected to MLPA.
  
  
  RESULTS
  HER2 amplification varied from 15% (ASCO/CAP 2007 HER2/CEP17 ratio) to 29.5% (FDA/EMA HER2 copy number). According to the ASCO/CAP 2013 interpretation of the dual-signal HER2 assay, ISH-positive carcinomas accounted for 19.7%. In contrast with the ASCO/CAP 2007 ratio, this approach labeled as positive all 32 cases (3.34%) with a HER2/CEP17 ratio <2 and an average HER2 copy number ≥6.0 signals per cell. In contrast, only one case showing a HER2 copy number <4 but a ratio ≥2 was diagnosed as positive. MLPA data correlated poorly with FISH results because of the presence of heterogeneous HER2 amplification in 33.9% of all amplified carcinomas; however, MLPA ruled out HER2 amplification in 75% of ISH-evaluated HER2-equivocal carcinomas.
  
  
  CONCLUSIONS
  The ASCO/CAP 2013 guidelines seem to improve the identification of HER2-positive carcinomas. Polymerase chain reaction-based methods such as MLPA can be of help, provided that heterogeneous amplification has been ruled out by ISH.
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy caterina.marchio@unito.it anna.sapino@unito.it.
authors.forename: Anna
authors.initials: A
authors.lastname: Sapino
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Maletta
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Ludovica
authors.initials: L
authors.lastname: Verdun di Cantogno
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Luigia
authors.initials: L
authors.lastname: Macrì
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Cristina
authors.initials: C
authors.lastname: Botta
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Gugliotta
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Maria Stella
authors.initials: MS
authors.lastname: Scalzo
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Annaratone
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Balmativola
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Pietribiasi
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Bernardi
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Arisio
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Viberti
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Guzzetti
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Renzo
authors.initials: R
authors.lastname: Orlassino
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Ercolani
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Marcella
authors.initials: M
authors.lastname: Mottolese
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Viale
authors.affiliation: Department of Medical Sciences, University of Turin, Turin, Italy; Pathology Unit, Department of Laboratory Medicine, Azienda Ospedaliera Città della Salute e della Scienza di Torino, Turin, Italy; Pathology Division, Santa Croce Hospital, Moncalieri, Italy; Pathology Division, Azienda USL Valle d'Aosta, Aosta, Italy; Pathology Division, Valdese Hospital, Turin, Italy; Pathology Division, Martini Hospital, Turin, Italy; Pathology Division, ASL 9, Civile Hospital, Ivrea, Italy; Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy; Division of Pathology, European Institute of Oncology, Milan, Italy; University of Milan School of Medicine, Milan, Italy caterina.marchio@unito.it anna.sapino@unito.it.
authors.forename: Caterina
authors.initials: C
authors.lastname: Marchiò
mesh_terms: D001324:Autoantigens / Q000235:genetics; D014408:Biomarkers, Tumor / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018797:Cell Cycle Proteins / Q000235:genetics; D015331:Cohort Studies; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D017408:Guidelines as Topic; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D016133:Polymerase Chain Reaction / Q000379:methods*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism
chemical_list: D001324:Autoantigens; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; C111329:CEP250 protein, human; C508053:ERBB2 protein, human
keywords: Breast cancer; Equivocal HER2 status; Guidelines; HER2 amplification; Heterogeneity