Background and objective: Lung cancer is one of the most common cancers worldwide and causes more deaths per year than other cancers. Autoantibody was one hotspot in tumor marker research. But the clinical value of Survivin autoantibody is not clear in lung cancer patients at present. The aim of this study is to determine whether Survivin autoantibody could be used as a diagnostic factor of lung cancer and what the clinical value of Survivin autoantibody was in nonsmall cell lung cancer (NSCLC).
Methods: Survivin cDNA sequence was obtained by RT-PCR and inserted into prokaryotic expression vector pET30a(+). Fusion protein of Survivin was expressed in E. coil BL21(DE3). SDS-PAGE and Western blot were used to confirm the fusion protein. The Survivin protein was purified by Ni-NTA agarose affinity chromatography. At last, indirect ELISA was used to detect Survivin autoantibody level in the serums of 215 samples from NSCLC patients and serums from 20 samples of nonmalignant lung disease patients as well as 89 samples of healthy persons were also detected as control.
Results: The recombinant vector pET30a(+)/Survivin was contructed and the Survivin protein is successfully expressed in E.coil BL21(DE3) as inclusion body. Indirect ELISA was done to detect Survivin autoantibody in these serums using purified Survivin protein. It was shown that the positive rate of Survivin autoantibody was 19.5%, with a specificity of 88.9% in NSCLC patients. The expression of Survivin autoantibody has correlation with the volume of tumor and the metastasis of tumor in NSCLC patients (P < 0.05). In our research, positive detection rate of NSCLC was much improved by detecting Survivin autoantibody combined with CEA compared to other tumor markers combined with CEA.
Conclusions: In this study, purified fusion protein of Survivin was successfully obtained. Indirect ELISA for detecting Survivin autoantibody in serum of NSCLC patients using purified Survivin protein was established. Our results indicated that Survivin autoantibody as a latent value of tumor marker could be used for clinical diagnosis in NSCLC patients.
背景与目的: 在世界范围内，恶性肿瘤已经成为威胁人类健康的主要原因，且其发病率和死亡率居高不下。随着人们对肿瘤标志物研究的不断深入，肿瘤相关的自身抗体成为了研究热点。肺癌患者血清中Survivin自身抗体的临床意义目前还存在争议。本研究旨在探讨Survivin自身抗体在非小细胞肺癌患者血清中可能的临床应用价值。
方法: 采用RT-PCR方法获得Survivin cDNA，构建原核表达载体pET30a(+)/Survivin，亲和层析方法纯化蛋白，SDS-PAGE电泳及Western blot鉴定，建立基于Survivin融合蛋白的间接ELISA方法，对89例健康志愿者、215例非小细胞肺癌患者以及20例肺部良性疾病患者的血清样本进行检测。
结果: 重组Survivin融合蛋白在BL21(DE3)中以包涵体形式高效表达，间接ELISA方法检测Survivin自身抗体在非小细胞肺癌患者血清中的阳性率为19.5%，特异性为88.9%，Survivin自身抗体与非小细胞肺癌患者的肿瘤大小、远处转移间存在相关性（P < 0.05），Survivin自身抗体与CEA在非小细胞肺癌患者中联合检测的阳性率明显高于CEA与NSE、SCC、CYFRA、ProGRP联合检测的阳性率，这大大提高了非小细胞肺癌检测的敏感性。
结论: 本研究成功构建原核表达载体pET30a(+)/Survivin，并建立检测Survivin自身抗体的间接ELISA方法，Survivin自身抗体与肺癌肿瘤大小、远处转移间的相关性及在非小细胞肺癌患者联合检测中的重要作用，为Survivin自身抗体在肺癌中的临床应用提供了线索和依据。