title: The Reliability of Endoscopic Biopsies in Assessing HER2 Status in Gastric and Gastroesophageal Junction Cancer: A Study Comparing Biopsies with Surgical Samples.
abstract: OBJECTIVE
  The aim of this study is to validate the accuracy of HER2 assessment on biopsies by comparing matched biopsy/surgical material from the same patients.
  
  
  METHODS
  HER2 status was evaluated by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in 103 cases of gastric and gastroesophageal junction cancers in coupled biopsy and surgical material.
  
  
  RESULTS
  Complete concordance between IHC and FISH results on biopsy versus surgical samples was noted in 80% and 95% of cases, respectively. At comprehensive comparison, including IHC and FISH data on biopsy and surgical samples, 89% of biopsies were predictive of HER2 status in surgical samples, whereas 11% showed variable inconsistencies. The majority of these (10 of 12 cases) showed IHC score 0/1+ on biopsy but were all IHC positive and amplified at surgery; in particular, three (3 of 35; 8.5%) IHC score 0 and four (4 of 16; 25%) IHC score 1+ cases were FISH amplified on biopsy material also, whereas the remaining three cases were FISH non-amplified on biopsy. The percentage of cases, which were FISH amplified with IHC score 1+ or 2+ on biopsies, were similar (25% and 33%, respectively) and they also shared a similar grade of amplification. These data suggest that both IHC score 1+ and 2+ on biopsy material represent "equivocal cases" that may merit further investigation.
  
  
  CONCLUSIONS
  The predictive value of HER2 IHC in biopsies is high. FISH analysis should be considered for IHC score 2+ and 1+ biopsy cases. Approximately 8% of cases will not be accurately predicted by biopsy evaluation.
authors: Department of Surgical and Diagnostic Sciences (DISC), Pathology Unit, University of Genoa and IRCCS San Martino-IST University Hospital, Genoa, Italy.
authors: Federica
authors: F
authors: Grillo
authors: Matteo
authors: M
authors: Fassan
authors: Chiara
authors: C
authors: Ceccaroli
authors: Cinzia
authors: C
authors: Giacometti
authors: Monica
authors: M
authors: Curto
authors: Vittorina
authors: V
authors: Zagonel
authors: Paola
authors: P
authors: Ceppa
authors: Donato
authors: D
authors: Nitti
authors: Carlo
authors: C
authors: Castoro
authors: Roberto
authors: R
authors: Fiocca
authors: Massimo
authors: M
authors: Rugge
authors: Luca
authors: L
authors: Mastracci