HER-2 expression and clinical significance in esophagogastric junction adenocarcinoma (Siewert type Ⅱ)

Abstract

To investigate the human epidermal growth factor receptor-2 (HER-2) expression in esophagogastirc junction adenocarcinoma(Siewert type Ⅱ)and its clinical significance. A total of 180 patients with esophagogastric junction adenocarcinoma (Siewert type Ⅱ) were included in this study. The HER-2 expression was detected by immunohistochemistry (IHC), and fluorescence in situ hybridization (FISH) analysis was performed to assess the HER-2 gene amplification in the IHC-positive and IHC-weak positive cases. HER-2 overexpression (3+ ), weak positive (2+ ) and negative (1+ /0) was 11.7%(21/180), 8.9%(16/180), and 79.4%(143/180), respectively. The FISH analysis showed HER-2 gene amplification in 95.2%(20/21) of HER-2(3+ ) cases and 18.8% (3/16) of HER-2(2+ ) cases. The concordance rate between IHC and FISH was 95.2%. Overexpression of HER-2(3+ ) was associated with the tumor differentiation (P<0.05), and irrelevant to age, sex, pT stage, pN stage, pM stage and pTNM stage (P>0.05). The median overall survival time (OS) was 13 months in HER-2(3+ ) patients, significantly shorter than the 21 months in HER-2(2+ ) and HER-2(+ /-) cases (P<0.01). Approximately 11.7% of the patients with esophagogastric junction adenocarcinoma (Siewert type Ⅱ) are HER-2-positive on IHC. HER-2 overexpression is associated with the tumor differentiation. IHC can be used as a screening test for the positive expression of HER-2 in the esophagogastirc junction adenocarcinoma (Siewert type Ⅱ). However, FISH detection can be used as a more reliable detection method.