Prevalence and Prognostic Significance of HER2 Amplification in Adenocarcinoma of the Esophagus and GE Junction.
Oana Radu, Katie Nason, Jon Davison. UPMC, Pittsburgh, PA
Background: The ToGA trial showed that trastuzumab (a monoclonal antibody targeting HER2) with conventional chemotherapy improves survival in advanced gastric or GE junction (GEJ) adenocarcinoma, underscoring the therapeutic importance of HER2 amplification and overexpression. There are conflicting reports of the prognostic significance of HER2 amplification in esophageal or GEJ adenocarcinoma (EAC). In this study we assess the association of HER2 amplification with pathologic features and survival in a large series of EAC treated by esophagectomy.
Design: 82 patients who underwent esophagectomy from 2000-2004 for EAC were prospectively evaluated for HER2 amplification. Dual-color FISH using a HER2 region probe and a chromosome 17 centromeric probe (CEP17) (Pathvysion, Abbott Molecular) was performed on paraffin sections of the resected tumor (N=79) or pre-operative biopsy (N=3). Pathologic, clinical and survival data was obtained for all patients by review of the medical record.
Results: Twenty-seven of 82 (32.9%) patients had HER2 amplification using a HER2/CEP17 ratio cutoff of 2.2. The HER2/CEP17 range for amplified cases was 2.2 – 42.6. The distribution of these results is summarized in Table 1.
|HER2/CEP17 Ratio||Number of Cases (%)|
|> 4.0||10 (12.2)|
|< 1.5||41 (50.0)|