血清CEA阴性结直肠癌患者血清差异蛋白质的初步筛选

目的分析血清CEA阴性结直肠癌患者、血清CEA阳性结直肠癌患者与正常人血清中差异表达蛋白，筛选潜在的与血清CEA阴性结直肠癌患者诊断及预后密切相关的血清蛋白质。方法血清CEA阴性结直肠癌患者、血清CEA阳性结直肠癌患者与正常人空腹血清标本各11例分别等量混合成3组样本，利用双向凝胶电泳（2-DE）及基质辅助激光解吸电离飞行时间质谱（MALDI_TOF-MS／MS）技术筛选及鉴定差异表达的蛋白点，并对其部分蛋白进行生物学分析。结果筛选出3组间表达量差异2倍以上差异蛋白点共13个，进行MALDI-TOF-MS／MS分析，鉴定出：①血清CEA阴性结直肠癌患者与正常人血清比较，表达下调的蛋白有纤维胶凝蛋白2前体，纤维胶凝蛋白3，载脂蛋白L1，间a胰蛋白酶抑制剂轻链H4，转甲状腺素蛋白，表达上调的蛋白为免疫球蛋白lambda轻链。②血清CEA阳性结直肠癌患者与正常人血清比较，表达下调的蛋白有纤维胶凝蛋白2前体，纤维胶凝蛋白3，载脂蛋白L1，间a胰蛋白酶抑制剂轻链H4，转甲状腺素蛋白，表达上调的蛋白为：载脂蛋白E，结合珠蛋白。③血清CEA阴性结直肠癌患者与血清CEA阳性结直肠癌患者的1个差异点，经鉴定为免疫球蛋白lambda轻链。结论血清CEA阴性结直肠癌患者与血清CEA阳性结直肠癌患者、正常人血清的蛋白质表达谱表现出一定差异，这些差异蛋白有可能成为血清CEA阴性结直肠癌患者诊断与判定预后的血清标志物。

Screening of differential serum proteins in serum CEA negative colorectal cancer patients

Objective To compare and analyze the expression difference of proteins between serum CEA negative colorectal cancer(CRC) patients,CEA positive CRC patients with healthy individuals to search for protein biomarkers that may be detected in serum of CEA negative CRC patients.Methods Pooled sera from 11 CEA negative CRC patients,11 CEA positive CRC patients and 11 healthy individuals as controls were collected.Two-dimensional gel electrophoresis(2-DE) was used to isolate the total proteins,the differential protein spots were identified by MALDI-TOF-MS/MS.The biological information of the proteins was analysis.Results 13 protein spots with more than 2-fold different between the three groups were selected and were identified by MALDI-TOF-MS/MS.Compared with healthy controls,the spots that were down-regulated in CEA negative cancer patients were: sficolin 2 isoform a precursor,ficolin 3;apolipoprotein L1;inter-alpha-trypsin inhibitor heavy chain H4;transthyretin(TTR),one spot was up regulated and was identified as Ig lambda light chain.Compared with healthy controls,the spots that were down-regulated in CEA positive cancer patients were : ficolin 2 isoform a precursor;ficolin 3;apolipoprotein L1;inter-alpha-trypsin inhibitor heavy chain H4;transthyretin(TTR),the spots that up-regulated were: Apolipoprotein E;spot haptoglobin.Compared with healthy controls,CEA positive cancer patients,one spot was up regulated and: Ig lambda light chain.Conclusion Compared with CEA positive CRC patients group and the normal subject group,the serum proteins in CEA negative CRC patients group showed differential expression in protein profile.The proteins of differential expression are expected to be the serum markers for CEA negative CRC patients.