title: Thymidine kinase 1 as a diagnostic tumor marker is of moderate value in cancer patients: A meta-analysis.
abstract: Thymidine kinase 1 (TK1) is an enzyme involved in nucleic acid synthesis and is therefore considered to be an important tumor proliferation marker. The aim of the present study was to determine the diagnostic role of TK1 measurement in cancer. An extensive electronic search was performed in PubMed, EMBASE and the Cochrane Library using the keywords 'thymidine kinase 1' and 'tumor' and synonyms. This study was conducted as part of a project to establish evidence-based guidelines for the diagnosis and treatment of cancer. A total of 453 abstracts were screened, after which the full text of 40 studies were selected for further investigation, including screening of the references cited by studies in the original search. Fifteen studies were enrolled following full-text evaluation. The areas under the receiver operating characteristic curves for the radioenzymatic assay (REA), the chemiluminescence immunoassay (CLIA) and the total were 0.88, 0.75 and 0.8, respectively. These results were all between <0.9 and >0.7, which suggested a moderate diagnostic efficacy. The positive likelihood ratio of the CLIA method was the highest (10.229), which demonstrated that CLIA exhibited a satisfactory specificity in tumor diagnosis. However, TK1 as a single diagnostic tumor marker was not of significant value and the combination of more tumor markers in the diagnosis of tumors may be preferable.
authors.affiliation: Department of Nasopharyngeal Carcinoma, Sun Yat-Sen University Cancer Center, Guangzhou, Guangdong 510080, P.R. China.
authors.forename: Yanqun
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Department of Clinical Laboratory, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Zeng
authors.affiliation: Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Departments of Ear-Nose-Throat, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Xiang
authors.initials: X
authors.lastname: Liu
authors.affiliation: Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Gynaecology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Clinical Laboratory, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Ling
authors.initials: L
authors.lastname: Luo
authors.affiliation: Department of Clinical Laboratory, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Chaohui
authors.initials: C
authors.lastname: Duan
authors.affiliation: Department of Clinical Laboratory, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Luo
authors.affiliation: Department of Clinical Laboratory, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China ; Key Laboratory of Malignant Tumor Gene Regulation and Target Therapy of Guangdong Higher Education Institute, Sun Yat-Sen University, Guangzhou, Guangdong 510120, P.R. China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Yan
keywords: diagnostic test; meta-analysis; thymidine kinase 1; tumor marker