HER2Expression And Significance In Esophagogastric Juction Adenocarcinoma (Siewert Type Ⅱ) In China

Objectives: To investigate the human epidermal growth factor receptor2(HER2) expression in esophagogastirc junction adenocarcinoma（Siewerttype II）in China and its influencing factors.Methods: A total of180patients with esophagogastric junctionadenocarcinoma (Siewert type II) from China were retrospectively analyzedfor HER2expression with immunohistochemistry (IHC), and fluorescence insitu hybridization (FISH) analysis was used in IHC3+/2+cases to assessHER2gene amplification.Results: HER2overexpression (3+), equivocal (2+) and negative (1+/0)was11.7%(21/180),8.9%(16/180),79.4%(143/180), respectively inesophagogastirc junction adenocarcinoma（Siewert type II）from China.Thespecimens which were HER2overexpression (3+) and equivocal (2+)analyzed by FISH,95.2%(20/21),18.8%(3/16) samples showed HER2geneamplification, respectively. The overexpression of HER2(3+) was associatedwith well or moderately tumor differentiation (P<0.05), and irrelevant to age,sex, pT stage, pN stage, pM stage and pTNM stage (P>0.05). A highconcordance rate (95.2%) between IHC and FISH was demonstrated.Conclusions: Approximately11.7%of Chinese patients withesophagogastric junction adenocarcinoma (Siewert type II) wereHER2-positive on IHC. HER2overexpression was associated with well ormoderately differentiated carcinomas. The concordance rate between IHC andFISH was95.2%.