肝细胞癌门静脉癌栓相关血清小分子量蛋白质标志物的筛选

Screening low molecular weight protein biomarkers relevant to portal vein tumor thrombi in serum ofpatients with hepatoceilular carcinoma

目的筛选肝细胞癌门静脉癌栓相关的血清小分子量蛋白质标志物。方法收集健康志愿者、肝细胞癌无癌栓患者和肝细胞癌门静脉癌栓患者3组血清各l2份，用16％SDS-PAGE进行双向电泳，得到3组血清小分子量蛋白质表达图谱；经Image Master软件比对分析后，用基质辅助激光解析飞行时间质谱对差异点进行鉴定。结果在16％SDS-PAGE凝胶中，3×10^3～20×10^3区域内蛋白质条带间距较12．5％SDS-PAGE明显增宽，条带数目明显增多，且3组血清小分子量蛋白质表达图谱中均可清晰显示〈20×10^3的小分子量蛋白质斑点。组间比较显示，3组血清共有15个小分子量差异蛋白质点，经鉴定为5种蛋白质。与健康组比较，无癌栓组中载脂蛋白A-I、脂蛋白CⅢ、转甲状腺素蛋白和DNA拓扑异构酶Ⅱ表达降低，而结合珠蛋白-2表达增高；门静脉癌栓组5种蛋白质表达均较无癌栓组降低。结论在肝细胞癌的发生和发展过程中，血清小分子量蛋白质表达谱发生明显变化，差异表达的小分子量蛋白质有可能为肝细胞癌和门静脉癌栓早期预测及治疗监测提供参考。

Objective To screen low molecular weight protein biomarkers relevant to portal vein tumor thrombi （PVTT） in serum of hepatocellular carcinoma （HCC） patients. Methods Serum samples were obtained from 12 healthy volunteers, 12 HCC patients without PVTT and 12 HCC patients with PVTT, Using two-dimensional gel electrophoresis （2-DE） in which the second dimension was 16% SDS-PAGE, serum protein images of the 3 groups were analyzed by ImageMaster software. The differential protein spots were further identified by MALDI-TOF MS/MS. Results Comparing the results using 12.5% SDS-PAGE gel, there were more protein bands （between 3×10^3 and 20 ×10^3） and low molecular weight （MW） protein spots （〈 20×1 0^3） were clearly shown in the 16% SDS-PAGE gel. Fifteen differential protein spots representing 5 proteins were found in the 3 groups by inter-class comparison and they were then identified. Compared with those in the healthy group, apolipoprotein A-I, lipoprotein CⅢ, transthyretin and DNA topoisomerase Ⅱ were all down regulated in HCC groups and haptoglobin-2 was over expressed. All 5 proteins decreased more in the PVTT group than in the non-PVTT group. Conclusion The expression of low MW serum protein obviously changes in the beginning and in the progressive stage of HCC, and differentially expressed low MW proteins might be potential biomarkers in an early prognostic prediction and surveillance in the treatment for HCC and PVTT.