HER2 status in gastro‐oesophageal adenocarcinomas assessed by two rabbit monoclonal antibodies (SP3 and 4B5) and two <i>in situ</i> hybridization methods (FISH and SISH)

Abstract

HER2-positivity is present in a significant proportion of oesophago-gastric adenocarcinomas (24%), but at a lower rate in the distal stomach (7%). Sensitivity for amplification is higher with 4B5 IHC than with SP3. FISH and SISH yield identical results, but assessment is much easier with SISH. Our findings provide important guidance for HER2-testing in gastro-oesophageal adenocarcinomas for patients in whom anti-HER2 treatment is considered.