Expression Of Tumor Suppression Gene XEDAR In Human Gastric Cancer Tissues

Purpose:X-linked ectodermal dysplasia receptor (XEDAR) is a isolated member of the tumor necrosis factor receptor family that binds to ectodysplasin-A2(EDA-A2) and regulates cell proliferation, differentiation and apoptosis. The purpose of this study was to detect and analyze the expression of the tumor suppression gene XEDAR in gastric cancer tissues.Materials and Methods:Lanzhou University Second Hospital pathology department provided paraffin-embeded samples of poorly differentiated adenocarcinoma, moderately differentiated adenocarcinoma and gastritis. Lanzhou University Second Hospital gastroenterology offered 90 samples from 30 patients with gastroscope (30 cancer tissues,30 surrounding normal tissues and 30 normal tissues in gastric.) between november 2010 and february 2011. The normal stomach tissues selection place is away from cancer tissues place> 5cm, and 2cm between surrounding normal tissues and cancer tissues. All tissues were conserved in -80℃refrigerator after they exsomatized. The group of poorly differentiated adenocarcinoma contains poorly differentiated adenocarcinoma and moderately-poorly differentiated adenocarcinoma, altogather 18 patients. The group of moderately-well differentiated adenocarcinoma contains moderately differentiated adenocarcinoma, moderately-well differentiated adenocarcinoma and well differentiated adenocarcinoma, altogather 12 patients. We detected and analyzed the expression of XEDAR in gastric cancer tissues and surrounding normal tissues using Immunohistology-Paraffin and Western-blot analysis, and analyzed data using SPSS 17.0 software package.Results:This study shows that XEDAR protein is located on cytoplasmic membrane in normal gastric tissues, and express seldom on cytoplasmic membrane or translocate from cytoplasmic membrane to cytoplasm in gastric cancer tissues. In poorly differentiated adenocarcinoma group the expression of XEDAR in gastric cancer tissues was significantly downregulated compared with that in surrounding normal tissues and normal tissues(P<0.01); the expression of XEDAR in surrounding normal tissues was significantly downregulated compared with that in normal tissues(P<0.01). In moderately-well differentiated adenocarcinoma group the expression of XEDAR in gastric cancer tissues was significantly downregulated compared with that in surrounding normal tissues and normal tissues(P<0.01); the expression of XEDAR in surrounding normal tissues was equalled that in normal tissues(P>0.05). The expression of XEDAR in poorly differentiated adenocarcinoma gastric cancer tissues was significantly downregulated compared with that in moderately-well differentiated adenocarcinoma gastric cancer tissues (P<0.01); The expression of XEDAR in poorly differentiated adenocarcinoma surrounding normal tissues was significantly downregulated compared with that in moderately-well differentiated adenocarcinoma surrounding normal tissues (P<0.01); but The expression of XEDAR in poorly differentiated adenocarcinoma normal tissues was equalled that in moderately-well differentiated adenocarcinoma normal tissues(P>0.05).Conclusions:The translocation of XEDAR protein from cell membrane to cytoplasm. This mutation attenuated the growth-suppressive effect of XEDAR. The low expression of XEDAR may contribute to accelerated tumor development. XEDAR may represent a novel gastric tumor suppressor gene, and the expression of XEDAR could be a marker for gastric cancer development and differentiation level.