Prevalence of HER2/neu overexpression/amplification in a Hispanic population with gastric adenocarcinoma.

25 Background: In Europe, Asia, and North America, studies have identified that approximately 20% of patients with gastric adenocarcinoma exhibit overexpression of HER2/neu. This group of patients has been shown to benefit from combination therapy with the anti-HER2/neu monoclonal antibody trastuzumab. These findings have not been studied in Hispanics who may possess a distinct gastric cancer genotype. The aim of this study is to determine the rate of HER2/neu positivity in a completely Hispanic population with gastric adenocarcinoma and to analyze the clinical factors associated with HER2/neu. Methods: We conducted a retrospective study in three different hospitals in Monterrey, Mexico. The study population consisted of Hispanic patients with gastric adenocarcinoma who have had a gastric resection and for whom there were adequate amounts of tissue available in paraffin blocks. Tissue was tested for HER2/neu using both Immunohistochemistry (IHC) and the fluorescent in situ hybridization (FISH) techniques....