AIM : To investigate the alteration and significance of the protein expression profile in gastric cancer with preoperative conformal radiation therapy.METHODS : The pathologically - diagnosed gastric cancer patients were randomly chosen to perform conformal radiation therapy before operation.The patients without conformal radiation treatment served as controls.The tumor tissues were collected after operation from the patients.The alteration of the protein expression profile was detected by 2 - dimensional electrophoresis and MALDI - TOF - MS.The expression of vascular endothelial growth facto( VEGF ) ,c - erbB - 2 and epidermal growth factor receptor( EGFR ) was detected by RT - PCR and Western blotting.RESULTS: Compared with the patients without conformal radiation therapy, the protein expression profile of tumor tissues from gastric cancer patients with conformal radiation therapy was obviously altered.The expression of VEGF,c - erbB - 2 and EGFR was differentially reduced( P ＜ 0.01 ).CONCLUSION : The preoperative accurate conformal radiation therapy reduces the expression of gastric cancer - related epithelial proteins, indicating new therapeutic targets for gastric cancer.%目的:探讨胃癌术前适形放疗作用后的蛋白表达谱变化及意义.方法:选择有病理诊断的胃癌患者,随机分组行单纯手术和适形放疗+手术,术后收集肿瘤组织标本.以固相pH 梯度等电聚焦(IPG-IEF) 为第一向、垂直平板十二烷基硫酸钠-聚丙烯酰胺凝胶电泳(SDS-PAGE) 为第二向进行胃癌组织蛋白质分离;用图像分析软件 PDQuest 8.0 分析电泳图谱,寻找有意义的差异蛋白点;运用MALDI-TOF质谱鉴定,并对其中差异显著蛋白采用Western blotting 和RT-PCR进行鉴定,检测蛋白表达谱变化.结果:胃癌适形放疗组与对照组的蛋白表达谱明显不同,发现3个有意义的差异蛋白质点,适形放疗组肿瘤细胞血管内皮生长因子(VEGF)、c-erbB-2和表皮生长因子受体(EGFR)的表达降低,与对照组比较差异显著(P＜0.01).结论:胃癌术前适形放疗可以降低胃癌细胞相关表皮蛋白表达.这些蛋白可能成为胃癌治疗新的靶点.
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