The reliability of endoscopic biopsies in assessing HER2 status in gastric and gastroesophageal junction cancer: A study comparing biopsies with surgical samples

Federica Grillo, Matteo Fassan, Chiara Ceccaroli, Cinzia Giacometti, Monica Curto, Vittorina Zagonel, Paola Ceppa, Donato Nitti, Carlo Castoro, Roberto Fiocca, Massimo Rugge, Luca Mastracci

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Abstract

AIM: The aimof 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. RESULT: 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.

Original languageEnglish
Pages (from-to)10-16
Number of pages7
JournalTranslational Oncology
Volume6
Issue number1
DOIs
Publication statusPublished - 2013

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ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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