title: SISH/CISH or qPCR as alternative techniques to FISH for determination of HER2 amplification status on breast tumors core needle biopsies: a multicenter experience based on 840 cases.
abstract: BACKGROUND
  Until now, FISH has been the gold standard technique to identify HER2 amplification status in ambiguous cases of breast cancer. Alternative techniques have been developed to increase the capacities of investigating HER2 amplification status. The aims of this multicenter study in a large series of breast cancer patients were to prospectively compare the level of performance of CISH, SISH, and qPCR alternative techniques on paraffin-embedded core biopsies with "gold standard FISH" for evaluation of HER2 amplification status.
  
  
  METHODS
  This study was performed on 840 cases scored by immunohistochemistry (IHC): 0=317 (38%), 1+=183 (22%), 2+=109 (13%), 3+=231 (27%). Each of the 15 French centers participating in the study analyzed 56 breast carcinoma cases diagnosed on fixed paraffin-embedded core biopsies. HER2 amplification status was determined by commercially available FISH used as the reference technique with determination of the HER2/CEN17 ratio or HER2 copy number status. The alternative techniques performed on the same cases were commercially available SISH or CISH and a common qPCR method especially designed for the study including a set of 10 primer pairs: 2 for HER2 (exons 8 and 26), 5 to evaluate chromosome 17 polysomy TAOK1, UTP6, MRM1, MKS1, SSTR2 and 3 for diploidy control TSN, LAP3 and ADAMTS16.
  
  
  RESULTS
  The concordance between IHC and FISH was 96% to 95% based on the HER2/CEN17 ratio (n=766) or HER2 copy number (n=840), respectively. The concordance of the alternative techniques with FISH was excellent: 97% and 98% for SISH (498 and 587 cases), 98% and 75% for CISH (108 and 204 cases) and 95% and 93% (699 and 773 cases) for qPCR based on the HER2/CEN17 ratio or HER2 copy number, respectively. Similarly, sensitivity ranged from 99% to 95% for SISH, 100% to 99% for CISH and 89% to 80% for qPCR. The concordance with FISH (ratio) in the 2+ cases was 89% for SISH, 100% for CISH and 93% for qPCR.
  
  
  CONCLUSIONS
  These alternative techniques showed an excellent concordance with FISH in core biopsies allowing their use in routine clinical practice. This newly designed qPCR on paraffin-embedded core biopsies deserves special attention, as it is reliable, easy to perform and less expensive than ISH tests.
authors.affiliation: Institut Paoli Calmettes, biopathology department, 232 Bd Ste Marguerite, 13009, Marseille, France. jacquemierj@ipc.unicancer.fr
authors.forename: Jocelyne
authors.initials: J
authors.lastname: Jacquemier
authors.forename: Frédérique
authors.initials: F
authors.lastname: Spyratos
authors.forename: Benjamin
authors.initials: B
authors.lastname: Esterni
authors.forename: Marie-Joëlle
authors.initials: MJ
authors.lastname: Mozziconacci
authors.forename: Martine
authors.initials: M
authors.lastname: Antoine
authors.forename: Laurent
authors.initials: L
authors.lastname: Arnould
authors.forename: Sarab
authors.initials: S
authors.lastname: Lizard
authors.forename: Philippe
authors.initials: P
authors.lastname: Bertheau
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lehmann-Che
authors.forename: Cécile Blanc
authors.initials: CB
authors.lastname: Fournier
authors.forename: Sophie
authors.initials: S
authors.lastname: Krieger
authors.forename: Frédéric
authors.initials: F
authors.lastname: Bibeau
authors.forename: Pierre-Jean
authors.initials: PJ
authors.lastname: Lamy
authors.forename: Marie Pierre
authors.initials: MP
authors.lastname: Chenard
authors.forename: Michèle
authors.initials: M
authors.lastname: Legrain
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Guinebretière
authors.forename: Delphine
authors.initials: D
authors.lastname: Loussouarn
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Macgrogan
authors.forename: Isabelle
authors.initials: I
authors.lastname: Hostein
authors.forename: Marie Christine
authors.initials: MC
authors.lastname: Mathieu
authors.forename: Ludovic
authors.initials: L
authors.lastname: Lacroix
authors.forename: Alexander
authors.initials: A
authors.lastname: Valent
authors.forename: Yves Marie
authors.initials: YM
authors.lastname: Robin
authors.forename: Françoise
authors.initials: F
authors.lastname: Revillion
authors.forename: Magali Lacroix
authors.initials: ML
authors.lastname: Triki
authors.forename: Aline
authors.initials: A
authors.lastname: Seaume
authors.forename: Anne Vincent
authors.initials: AV
authors.lastname: Salomon
authors.forename: Patricia
authors.initials: P
authors.lastname: de Cremoux
authors.forename: Geneviève
authors.initials: G
authors.lastname: Portefaix
authors.forename: Luc
authors.initials: L
authors.lastname: Xerri
authors.forename: Sophie
authors.initials: S
authors.lastname: Vacher
authors.forename: Ivan
authors.initials: I
authors.lastname: Bièche
authors.forename: Frédérique
authors.initials: F
authors.lastname: Penault-Llorca
mesh_terms: D062005:Biopsy, Large-Core Needle; D001943:Breast Neoplasms / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018734:Genes, erbB-2 / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods*; D008875:Middle Aged; D011237:Predictive Value of Tests; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*