新的肺癌血清标志物——甲状腺运载蛋白

A New Serum Biomarker for Lung Cancer-Transthyretin

背景与目的肺癌是当今世界上最常见的恶性肿瘤之一,迄今缺乏临床诊断可用的分子标志物。本实验应用SELDI技术寻找肺癌新的血清标志物。方法对227例血清样品(包括146例肺癌、13例肺炎、28例结核性胸膜炎和40例正常人血清样品)进行蛋白质谱检测。对候选蛋白进行质谱鉴定,并结合免疫共沉淀和ELISA技术筛选出肺癌新的候选标志物。结果通过Biomarker WizardTM软件分析显示13.78kDa、13.90kDa和14.07kDa的蛋白峰在肺癌病人血清样品中明显低于对照组。通过1-D胶分离,质谱鉴定和免疫沉淀分析显示这3个差异蛋白峰为野生型甲状腺运载蛋白(nativeTTR)和它的两个变体(cysTTR and glutTTR)。ELISA和SELDI技术分析上述血清样品均发现TTRs在肺癌血清中的表达下调。结论采用SELDI技术首次筛选并鉴定出TTRs,表明其可能作为肺癌诊断的候选血清标志物。

Background and objective Lung cancer is the leading cause of cancer death worldwide and very few specific biomarkers could be used in clinical diagnosis at present. The aim of this study is to find novel potential serum biomarkers for lung cancer using Surface Enhanced Laser Desorption/Ionization （SELDI） technique. Methods Serum sample of 227 cases including 146 lung cancer, 13 pneumonia, 28 tuberculous pleurisy and 40 normal individuals were analyzed by CM10 chips. The candidate biomarkers were identified by ESI/MS-MS and database searching, and further confirmed by immunoprecipitation. The same sets of serum sample from all groups were re-measured by ELISA assay. Results Three protein peaks with the molecular weight 13.78 kDa, 13.90 kDa and 14.07 kDa were found significantly decreased in lung cancer serum compared to the other groups and were all automatically selected as specific biomarkers by Biomarker Wizard software. The candidate biomarkers obtained from 1-D SDS gel bands by matching the molecular weight with peaks on CM10 chips were identified by Mass spectrometry as the native transthyretin （native TTR）, cysTTR and glutTTR, and the identity was further validated by immunoprecipitation using commercial TTR antibodies. Downregulated of TTR was found in both ELISA and SELDI analysis. Conclusion TTRs acted as the potentially useful biomarkers for lung cancer by SELDI technique.