中文摘要：

目的：探讨血浆DNA含量及完整性指数在早期胃癌诊断中的临床应用价值。方法：收集28例Ⅰ/Ⅱ期胃癌术前患者、18例胃良性疾病和28例正常个体外周血标本。通过扩增重复短片段ALU115和长片段ALU247,检测血浆游离DNA含量及完整性指数。结果：血浆ALU115片段含量在早期胃癌组较良性组和正常组明显升高（P=0.0017）。但是完整性指数在三组之间未见到统计学差异。结论：联合检查ALU115和传统肿瘤标记物可以有效筛查早期胃癌。血浆DNA的含量在早期胃癌的筛查中有临床应用价值。

英文摘要：

Objective：To explore the value of the conteration and integrity index of circulating cell- free DNA in plasma for the diagnosis of early gasric cancer parients. Methods： Plasma samples were collected from 28 patients with srage Ⅰ - Ⅱ gastric cancer, 18 patients with gastric benign diseases and 28 healthy controls. Long（247bp） and short （115 bp） DNA fragments of ALU fragments in plasmas were detected by Real - time qualitative PCR. Results：The median plamsa ALU115 content in early gastric cancer group was significanticly higher than those in gastric begin and healthy control groups（P = 0.0017）. But there was no difference in ALU247 content and DNA integrity among three groups. Combining the ALUll5 content and clinicalused tumor markers could improve the distinguishing effecincy for early gastric cancer. Conclusion：Plamsa DNA concentration assessed by ALU115 content may be valuable in indentifying early gastric cancer.