应用iTRAQ技术构建胃癌唾液的蛋白质组差异表达谱

目的：应用同位素标记相对和绝对定量（iTRAQ）技术标记定量蛋白组技术对胃癌患者唾液的全组蛋白进行鉴定和定量分析，初步获得胃癌患者唾液的蛋白组差异表达图谱。方法：胃癌患者与正常人唾液各10例，各组等量混合后利用iTRAQ8标试剂标记后的样本，采用Nano—LC—Ms／Ms分离、分析肽段，运用Proteinpilot4．0软件对蛋白进行鉴定和定量分析，并比较这些蛋白的表达差异。结果：对样品进行了2次Nano—LC—Ms／Ms，标记率〉95％，错误发现率〈1％，鉴定出符合假阳性率〈1％，共鉴定了747个蛋白。与正常对照组相比，胃癌组共出现了2倍以上表达差异的蛋白质21个，其中上调的12个，下调的9个。结论：iTRAQ联合NanoLC—MS／MS技术能高通量地筛选胃癌患者唾液中相关的蛋白，为胃癌患者早期诊断和预后提供可能的生物学标志物或治疗靶点，建立一种无创、简便、快捷实用的检测评估手段。

Differential Expression Profiling of Proteome for Saliva of Patients with Gastric Cancer by Using iTRAQ Technology

d Objective To identify and quantify the total proteins in saliva of patients with gastric cancer by using quantitative proteomic isobaric tags for relative and absolute quantitation（iTRAQ） technology, and to establish a differential expression profiling of proteome for saliva of patients with gastric cancer. Methods 10 patients with gastric cancer were selected for the experiment group, 10 health individuals were selected for the normal control group, and their saliva samples were obtained respectively. After balanced mix respectively, the saliva samples were labeled and the peptides were separated and analyzed by iTRAQ technology combining with Naro- LC-Ms/Ms. The identification and quantitation of the proteins were analyzed by Proteinpilot 4.0 software, and the differential expression of these proteins were compared. Results The labeling efficien 95 %, the false discovery rates（FDRs） was less than 1% of the total identified 747 proteins cy was greater than in the experiment which were repeated two times by Nano LC-MS/MS. Compared with the normal control group, 21 proteins were discovered to be significantly differentially expressed with more than 2 folds in gastric cancer, among which 12 proteins were up-regulated and 9 proteins were down-regulated. Conclusion A high-throughput screen for proteins in saliva of patients with gastric cancer can be performed by using iTRAQ combining with Nano LCMS/MA, and provide the potential metastasis-related biomarkers and therapeutic targets in early diagnosis, treatment and prognosis for patients with gastric cancer, and establish a noninvasive, convenient, quick and pragmatic assessment testing method.