〈Originals〉The expression of human epidermal growth factor receptor 2 in peritoneal metastasis of gastric cancer

Abstract

[Abstract]　(Background) The prognosis of gastric cancer patients with peritoneal metastasis (PM) is very poor. In recent report suggested that a monoclonal antibody that targets human epidermal growth factor receptor 2 (HER2) improve the prognosis of gastric cancer with HER2 overexpression and/or gene amplification. However, HER2 overexpression and/or gene amplification of gastric patients with PM is unclear. (Methods) HER2 expression of primary gastric lesion and peritoneal metastasis was investigated immunohistologically and by fluorescence in-situ hybridization. Specimens were obtained from 15 patients with gastric cancer. (Results) There was no difference about the results of HER2 overexpression and gene amplification between primary gastric lesion and peritoneal metastasis. Fifteen gastric carcinoma tissue samples were classified as follows: 12 (80％) were scored as 0, 1 (6.7％) as 1, 2 (13.3％) as 2, and 0 (0％) as 3. Two specimens 2+ for HER-2 expression with immunohistological staining were analyzed by fluorescence in-situ hybridization. HER-2 gene amplification was not determined in these samples. (Conclusion) Primary gastric lesion and peritoneal metastasis of gastric cancer did not show HER2 amplification and/or overexpression. Further, prospective, larger-scale studies are needed to evaluate the efficacy of monoclonal antibody that targets HER2 to GC patients with PM.Satou, Takao, Itoh, Tatsuk