Chaperonin containing TCP1 subunit 5 is a tumor associated antigen of non-small cell lung cancer

// Hongjun Gao 1, * , Min Zheng 2, * , Sijin Sun 5, * , Hongwu Wang 3 , Zhigang Yue 1 , Yun Zhu 1 , Xiaochen Han 2 , Junquan Yang 2 , Yanqiu Zhou 1, 3 , Yiran Cai 4 and Wanning Hu 2 1 Department of Clinical Laboratory, China Meitan General Hospital, Beijing, PR China 2 Department of Oncology, Tangshan People’s Hospital & Tangshan Cancer Hospital, North China University of Science and Technology, Tangshan, PR China 3 Department of Oncology, China Meitan General Hospital, Beijing, PR China 4 Department of Pathology, Beijing Chest Hospital, Capital Medical University & Beijing Tuberculosis and Thoracic Tumor Research Institute, Beijing, PR China 5 Department of Clinical Medicine, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, PR China * These authors have contributed equally to this work Correspondence to: Hongjun Gao, email: gaohj007@126.com Yanqiu Zhou, email: yanqiuz@sina.com Wanning Hu, email: rmyy_hwn@163.com Yiran Cai, email: cyr_71@163.com Keywords: CCT5, non-small cell lung cancer, CEA, CYFRA 21-1 Received: February 24, 2017 Accepted: June 18, 2017 Published: July 18, 2017 ABSTRACT Novel tumor antigens and their related autoantibodies have tremendous potential for early diagnosis of non-small cell lung cancer (NSCLC). In this study, we identify antigens from NSCLC tissue and autoantibodies in sera of patients with NSCLC using a modified proteomics-based approach. We seperated and identified four NSCLC-associated proteins extracted from the cytosol in tumor tissues by mini-two-dimensional gel electrophoresis, followed by Western blot and hybridization with individual sera for confirmation of antibody binding. Of the proteins we identified, we selected 58 kDa chaperonin containing TCP1(T-Complex Protein 1) subunit 5 (CCT5) for validation. Serum levels of carcinoembryonic antigen (CEA) and cytokeratin 19 fragments (CYFRA 21-1) were measured in all serum samples with an immunoluminometric assay and a receiver operating characteristic (ROC) curve was analyzed for autoantibodies against CCT5, CEA and CYFRA 21-1. The results show that CCT5 can induce an autoantibody response in NSCLC sera and show higher expression in NSCLC tissues by immunohistochemistry and Western blot. Anti-CCT5 autoantibody was found in 51% (23/45) of patients with NSCLC, but only 2.5% (1/40) in non-tumor individual controls. A receiver operating characteristic curve constructed with a panel of autoantibodies against CCT5 (AUC=0.749), CEA (AUC=0.6758), and CYFRA 21-1(AUC=0.760) show a sensitivity of 51.1% and 97.5% specificity in discriminating NSCLC from matched controls. These results indicate the potential utility of screening autoantibodies in sera, show that CCT5 could be used as a biomarker in cancer diagnosis.