Comprehensive proteome analyses toward biomaker discovery for gastrointestinal and hepatobiliary cancers

为寻找新的胃肠道肿瘤生物标志物，采用蛋白质芯片技术（SELDI-TOF MS）和荧光双向差异凝胶电泳（2D-DIGE）相结合的方法，对食管癌及癌旁组织中表达改变的蛋白质进行分析和质谱鉴定。其中，一个195 kDa的蛋白，periplakin，在食管癌中显着下调，这是由免疫印迹证实。免疫组化结果显示，periplakin在正常上皮和不典型增生病变中主要定位于细胞-细胞边界，而在早期癌中periplakin从细胞边界消失，转移到胞浆，在晚期癌中几乎不表达，胰腺癌仍是预后极差的肿瘤之一。为了寻找这种癌症的新的血清生物标志物，利用蛋白质芯片系统（SELDI-TOF MS）。我们比较了行根治性胰腺切除术的浸润性胰腺导管癌患者术前和术后的血清学资料。我们发现6630 Da蛋白在术前血清中比术后血清中表达更丰富。结果发现，术前血清中高水平的这种蛋白表明预后较差。免疫组化显示6630 Da蛋白在胰腺癌细胞中大量表达，而在正常胰腺导管细胞中不表达。结合SELDI-TOF MS和2D-DIGE，我们可以检测和鉴定过量饮酒的几种生物标志物。

In search for novel biomarkers for gastrointestinal cancers, comprehensive proteome analyses were performed combining the ProteinChip system (SELDI-TOF MS) and fluorescent 2-D differential gel electrophoresis (2D-DIGE).Proteins with altered expression in primary esophageal cancer and adjacent non-cancer tissues were analyzed by agarose 2D-DIGE and identified by mass spectrometry. Among them, a 195-kDa protein, periplakin, was significantly downregulated in esophageal cancer, which was confirmed by immunoblotting. Imunohistochemistry showed that periplakin was mainly localized at cell-cell boundaries in normal epithelium and dysplastic lesions, while it disappeared from cell boundaries, shifted to cytoplasm, in early cancers and scarcely expressed in advanced cancers.Pancreatic cancer still remains one of the cancers with extremely poor prognosis. To find a novel serum biomarkers for this cancer, the ProteinChip system (SELDI-TOF MS) was utilized. We compared pre- and postoperative serum profiles obtained from patients with invasive pancreatic ductal carcinoma who underwent curative pancreatomy. We identified 6630Da protein as more abundantly expressed in preoperative serum than in postoperative serum. It was found that the high preoperative serum levels of this protein suggests poorer prognosis. Immunostaining revealed abundant expression of the 6630Da protein in pancreatic cancer cells, but not in normal pancreatic ductal cells.Habitual alcohol drinking is a risk factor for a variety of cancers. Combining the SELDI-TOF Ms and 2D-DIGE, we could detect and identify several biomarkers for excessive alcohol drinking.