Dan Huang 1 , Ning Lu 2 , Qinhe Fan 3 , Weiqi Sheng 1 , Hong Bu 4 , Xiaolong Jin 5 , Guimei Li 6 , Yanhui Liu 7 , Xianghong Li 8 , Wenyong Sun 9 , Huizhong Zhang 10 , Xiaobing Li 11 , Zongguang Zhou 12 , Min Yan 13 , Xuan Wang 14 , Weihong Sha 15 , Jiafu Ji 16 , Xiangdong Cheng 17 , Zhiwei Zhou 18 , Jianming Xu 19 , Xiang Du 1 , *
14 November 2013
Trastuzumab has been approved for human epidermal growth factor receptor 2 (HER2)-positive advanced gastric and gastroesophageal junction cancers (GC and GJC) in combination with chemotherapy. The aim of this HER2 early/advanced gastric epidemiology (HER-EAGLE) study was to evaluate the frequency of HER2 over-expression and to evaluate agreement on HER2 status assessment in GC and GJC patients in local laboratories versus a central laboratory in China. Tumor samples from 734 GC or GJC patients who were enrolled at 11 different hospitals in China were examined. HER2 status was assessed by immunohistochemistry (IHC), and followed by dual-color silver-enhanced in Situ hybridization (DSISH) in IHC 2+ cases. Clinicopathologic characteristics were collected from all of the patients. HER2-positive tumors were identified in 12.0% (88/734) of the GC and GJC cases. There were significantly higher rates of HER2 positivity in patients with GJC (GJC: 18.1%, GC: 9.7%, P=0.002), and intestinal-type cancers using the Lauren classification (intestinal: 23.6%, diffuse/mixed: 4.3%, P<0.0001). No significant difference in HER2 positivity was identified between resection and biopsy samples, or between early and advanced disease stages. The agreement between local laboratories and the central laboratory on HER2 status scoring was good (kappa=0.86). The main reason of HER2 status discordance between local and the central laboratories was IHC result mis-interpretation in local laboratories. These results suggest that IHC followed by DSISH testing is an accurate and cost-effective procedure in China.