Abstract: Abstract: Objective To evaluate the gene amplification and protein expression of HER-2 in gastric carcinoma with or without neuroendocrine differentiation (NED), and to explore the difference in HER-2 gene profile between these two neo⁃ plasms. Methods Cases of gastric carcinoma with NED (n=70) and cases of gastric carcinoma without NED (n=150) were retrospectively reviewed. Gene amplification and protein expression of HER-2 genes in gastric carcinoma with or without NED were detected by combination of immunohistochemical method (IHC) and double color silver dye for in situ hybridiza⁃ tion (DISH). Prognosis of gastric cancer patients with NED were predicted using Kaplan-Meiers survival analysis. Results Expression rates of HER-2 in gastric cancer with and without NED are 20.00% and 21.33% respectively. Amplification of HER-2 in gastric cancer with and without NED are 8.57% and 14.67% respectively. Gene amplification and protein expres⁃ sion of HER-2 between gastric cancer with NED and without NED showed no statistical difference. Chromosome 17 multibody positively correlated with gene HER-2 amplification in Gastric carcinoma with NED. Postoperative survival period in patients of gastric carcinoma with NED and HER-2 amplification was shorter than that in patients of gastric carcinoma with⁃ out NED but with HER-2 amplification. Gastric carcinoma with or without NED, HER-2 gene amplification, lymph node me⁃ tastasis and operation method obviously correlate with prognosis of gastric carcinoma patients (P＜0.05). Conclusion The gastric cancer with NED is a special type of gastric cancer, there was no difference of gene amplification and protein expres⁃ sion of HER-2 gene between gastric carcinoma with NED and without NED. Poor prognosis would be expected in gastric can⁃ cer patients with NED and HER-2 amplification.

Key words: carcinoma, neuroendocrine, stomach neoplasms, proto-oncogene proteins, in situ hybridization, gene am? plification, HER-2, protein expression