中文摘要：

目的：应用同位素标记相对和绝对定量技术（ iTRAQ）结合二维液相色谱-串联质谱技术（2DLC-MS/MS）筛选前列腺癌差异表达蛋白。方法将前列腺穿刺活检的组织标本分为三组：良性前列腺增生组（20例）、前列腺癌组（20例）以及前列腺上皮内瘤组（10例）。对这些组织标本进行蛋白提取、定量和酶解。 iTRAQ标记后（其中114标记良性前列腺增生组，116标记前列腺癌组，117标记前列腺上皮内瘤组），进行2DLC-MS/MS分析。利用ProteinPilot软件（版本3.0）对MS/MS肽段进行分析，在International Swissprot （090210，human）数据库中搜寻蛋白并定量。差异表达蛋白界值设定：大于1.5倍或小于0.66倍且P＜0.05认为二者之间存在显著差异表达。 Western-blot 进一步验证了TPD52、Prohibitin-2、EF-Tu、Decorin 的表达。结果总共鉴定出760种蛋白。相对于良性前列腺增生，前列腺癌差异表达蛋白共有46个，其中有20个蛋白明显上调，26个蛋白明显下调。 Western-blot 的验证结果与这些蛋白的表达变化相符合。结论通过iTRAQ技术分析得到的前列腺癌差异表达蛋白可靠，iTRAQ技术为筛选出有意义的前列腺癌生物标记物提供了一个良好的平台。

英文摘要：

Objective To screen differentially expressed proteins of prostate cancer by the proteomics analysis using isobaric tags for relative and absolute quantification （ iTRAQ ） combined with two-dimensional liquid chromatography-tandem mass spectrometry （2DLC-MS/MS）.Methods The patients undergoing prostate biopsies were classified in 3 groups：benign prostate hyperplasia（n=20）,prostate cancer（n=20）and prostatic intraepithelial neoplasm（n=10）.After quantification and enzymolysis of the protein extract from the specimens of the 3 groups,the iTRAQ regents 114,116 and 117 were used to label the peptides of the 3 groups respectively .Then,the mixture of the peptides was analyzed by 2DLC-MS/MS.The MS/MS data were searched against the International Swissprot （090210,Human）using the Protein Pilot software（version 3.0）for peptide identification and quantification .The fold change cutoff ratio＆gt;1.50 or ＆lt;0.66 was selected to designate proteins of differential expression （ P＆lt;0.05 ） .Several differentially expressed proteins such as Tumor protein D 52（TPD52）,Prohibitin-2,Elongation factor Tu（EF-Tu）and Decorin were verified by Western-blot assay .Results A total of 760 proteins were identified from the International Swissprot （ 090210 , Human ） .Based on the condition of screening differentially expressed proteins , comparing with BPH,20 proteins were significantly up-regulated （ ＆gt;1.5-fold ） and 26 were significantly down-regulated in PCa （＆lt;0.66-fold）.TPD52,Prohibitin-2,EF-Tu were significantly up-regulated（4.25 fold,4.57 fold and 3.02 fold, respectively）and Decorin was down-regulated（0.43 fold）in PCa.The results of Western-blot assay were consistent with the proteomic changes of these 4 proteins.Conclusion The differentially expressed proteins of PCa identified by proteomic analysis using iTRAQ are reliable .The iTRAQ technology provides a good platform to identify more significant biomarkers of PCa .