Comprehensive proteome analyses toward biomaker discovery for gastrointestinal and hepatobiliary cancers

为寻找胃肠道肿瘤的新生物标志物，将蛋白质芯片系统(SELDI-TOF MS)和荧光二维差示凝胶电泳法(2D-DIGE)相结合，对食道癌和癌旁组织中表达改变的蛋白质进行琼脂糖凝胶电泳法分析，并用质谱仪进行鉴定。其中，一种195 kDa的蛋白Periplakin在食道癌中显著下调，免疫印迹证实了这一点。免疫组织化学显示，在正常上皮和异型增生病变中，周斑蛋白主要定位于细胞-细胞边界，在早期癌中消失，向胞浆转移，在晚期癌中几乎不表达。胰腺癌仍是预后极差的癌症之一。为了寻找一种新的癌症血清生物标志物，利用蛋白质芯片系统(SELDI-TOF MS)。我们比较了接受根治性胰腺手术的浸润性胰腺导管癌患者手术前后的血清标本。我们发现6630Da蛋白在术前血清中的表达高于术后血清中的表达。研究发现，术前血清中该蛋白水平较高提示预后较差。免疫染色显示6630Da蛋白在胰腺癌细胞中大量表达，但在正常胰腺导管细胞中不表达。习惯性饮酒是多种癌症的危险因素。结合SELDI-TOF MS和2D-DGE，我们可以检测和鉴定一些过度饮酒的生物标志物。

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.