人血清外泌体癌胚抗原检测在结直肠癌诊断中的临床应用

The clinical application value of human serum exosomal CEA in the diagnosis of colorectal cancer

目的分离鉴定人血清中的外泌体，探讨将外泌体癌胚抗原（CEA）作为结直肠癌诊断指标的可行性。方法回顾性研究。选择同济大学附属同济医院2015年10月至2016年12月确诊的结直肠癌病例组64例患者（血清CEA正常病例组41例及血清CEA增高病例组23例），良性结直肠疾病对照组20例患者及正常对照者40名。采用ExoQuick试剂盒从血清中提取外泌体，应用透射电镜、Western blot对外泌体进行形态学和分子表型鉴定；采用酶联免疫吸附试验（ELISA）法检测血清CEA及血清外泌体CEA浓度。利用U检验和受试者工作特征曲线（ROC）判断在结直肠癌中的诊断效能。结果采用ExoQuick试剂盒成功提取血清中的外泌体。ELISA法检测64例结直肠癌病例组外泌体CEA浓度为（1 056.36～28 637.78）pg/ml，显著高于良性疾病对照组（394.61～2 437.83）pg/ml以及正常对照组（610.89～2 076.70）pg/ml（分别U＝124.000，U＝119.000，均P〈0.001）；41例血清CEA正常病例组外泌体CEA浓度为（1 056.36～5 832.07）pg/ml，显著高于良性良性疾病对照组和正常对照组（分别U＝113.000，U＝119.000，均P〈0.001）；血清Exosomal CEA浓度对结直肠癌诊断的ROC曲线下面积为0.954（95% CI＝0.919～0.988），优于血清CEA浓度[0.636（95% CI＝0.531～0.742）]对结直肠癌的诊断效能。结论分离并检测血清外泌体CEA浓度对结直肠癌具有良好的诊断效能，有可能成为结直肠癌早期诊断标志物。（中华检验医学杂志，2018, 41：503-508）

ObjectiveTo isolate and identify exosomes from human serum, explore the feasibility of exosomal CEA for the diagnosis of colorectal cancer.MethodsRetrospective study.64 cases with colorectal cancer patients（41 cases with normal CEA results and 23cases with high CEA results）, 20 cases with benign colorectal diseases patients and 40 cases with healthy people of department of physical examination from October 2015 to December 2016 in Tongji Hospital of Tongji University. Exosomes were isolated from these serum using ExoQuick, and then identified by using transmission electron microscopy, and Western Blot for morphology and molecular phenotype.The serum level of CEA and exosomal CEA was measureed by enzyme linked immunosorbent assay （ELISA）. The diagnostic efficacy of serum Exosomal CEA concentration in the colorectal cancer by using U test and the subject work characteristic curve （ROC）. ResultsExosomes in human serum was successfully extracted with ExoQuick kit.Exosomal CEA concentration in 64 cases with colorectal cancer patients （1 056.36-28 637.78）pg/ml was significantly higher than in cases with benign colorectal diseases patients （394.61-2 437.83）pg/ml and healthy controls（610.89-2 076.70）pg/ml（U=124.000, U=119.000, P〈0.01）. Exosomal CEA concentration in 41 colorectal cancer patients with normal serum CEA concentration（1 056.36-5 832.07）pg/ml was significantly higher than in benign colorectal diseases patients and healthy controls（U=113.000, U=119.000; P〈0.01）. ROC analysis of exosomal CEA yielded an AUC（area under the ROC curve）of 0.954（95% CI=0.919-0.988）, which was higher than the serum CEA.The area under the ROC curve of serum Exosomal CEA concentration for colorectal cancer diagnosis is 0.954（95% CI=0.919-0.988）, which is superior to the serum CEA concentration[0.636 （95% CI=0.531-0.742）]. ConclusionsIsolation and detection of serum Exosomal CEA concentrations have a good diagnostic efficacy in colorectal cancer. It′s possible to be a marker for early diagnosis of colorectal cancer.（Chin J Lab Med, 2018, 41： 503-508）