WCX磁珠联合MALDI-TOF-MS技术在结直肠癌诊断中的应用

目的:比较结直肠癌与正常人血清蛋白质谱的变化,筛选特异性蛋白标志物,建立结直肠癌诊断分类树模型.方法:收集血清样本133例(其中结直肠癌67例,正常人66例),随机分为建模组和验证组.运用弱阳离子纳米磁珠(magnetic bead-weak cation exchange,MB-WCX)联合基质辅助激光解吸离子飞行质谱(matrix-assistedlaser desorption/ionization time-of-flight massspectrometry,MALDI-TOF-MS),建立结直肠癌与正常人血清蛋白质谱.用Flex Analysis2.4软件收集数据,应用ClinproTools2.2软件对建模组34例结直肠癌和33例正常人血清差异蛋白质谱进行定量分析,应用Genetic Algorithm算法建立结直肠癌诊断模型,应用所获取的诊断模型对验证组样本(33例结直肠癌和33例正常人)进行分类诊断,以评价诊断模型的诊断价值.结果:通过比较分析结直肠癌与正常人血清蛋白质谱,发现共有33个差异蛋白峰(P<0.05),其中在结直肠癌中表达上调25个,表达下调8个.利用其中5个差异峰(Mr分别为759,3316,4645,4248,2645Dr)建立诊断模型,获得了94.12%(32/34)敏感性和96.97%(32/33)的特异性,经独立样本双盲验证,其灵敏度为93.94%(31/33),特异度为96.97%(32/33).结论:基于磁珠分离和MALDI-TOF-MS技术能直接检测出结直肠癌患者血清差异表达蛋白,建立的诊断模型具有较高的敏感性和特异性,对提高结直肠癌的诊断具有一定的临床意义.

Diagnosis of colorectal cancer by MALDI-TOF-MS combined with WCX magnetic beads

AIM:To explore the difference in serum proteomic spectra between patients with colorectal cancer and healthy individuals,and to identify the specific protein biomarkers.METHODS:Serum samples collected from 67 colorectal cancer patients and 66 healthy individuals were randomized into model construction group and validation group.Magnetic beadsbased weak cation exchange(MB-WCX) kit and matrix-assisted laser desorption/ionization timeof-flight mass spectrometry(MALDI-TOF-MS) were used to profile serum proteome.Flex analysis software was used to analyze protein peaks for significant difference.A diagnostic model was then built using ClinproTools2.2software and evaluated blindly for reliability.RESULTS:Thirty-three differentially expressed proteins in serum were screened between colorectal cancer patients and healthy individuals,including 25 up-regulated proteins and 8 down-regulated ones.Five proteins(759,3316,4645,4248,and 2645 Dr) were used for building a ClinProt model which was able to classify colorectal cancer patients and healthy individuals with a sensitivity of 94.12%(32/34) and a specificity of 96.97%(32/33).A double blind validation test showed that the ClinProt model yielded a sensitivity of 93.94(31/33) and a specificity of 96.97%(32/33).CONCLUSION:Combination of MALDI-TOF-MS with WCX kit allows to directly screen proteins differentially expressed in the serum of patients with colorectal cancer,and these proteins can be used to diagnose early-stage colorectal cancer.