title: Association between circulating levels of IGF-1 and IGFBP-3 and lung cancer risk: a meta-analysis.
abstract: BACKGROUND
  The insulin-like growth factor (IGF) system was documented to play a predominant role in neoplasia. As lung cancer is one of the most malignant cancers, we conducted a meta-analysis in order to investigate the strength of association between circulating IGF-1 and IGFBP-3 levels and lung cancer.
  
  
  RESULTS
  A systematic literature search was conducted to identify all prospective case-control studies and case-control studies on circulating IGFs and IGFBPs levels. Six nested case-control studies (1 043 case subjects and 11 472 control participants) and eight case-control studies (401 case subjects and 343 control participants) were included in this meta-analysis. Pooled measure was calculated as the inverse variance-weighted mean of the natural logarithm of multivariate adjusted OR with 95% CIs for highest vs. lowest levels to assess the association of circulating IGF-1 and IGFBP-3 concentrations and lung cancer. Standard mean difference (SMD) was also calculated to indicate the difference of the circulating IGF-1 and IGFBP-3 concentrations between the lung cancer case group and the control group. Of the nested case-control studies, ORs for the highest vs. lowest levels of IGF-1 and IGFBP-3 were 1.047 (95% CI: [0.802,1.367], P = 0.736) and 0.960 (95%CI: [0.591,1.559], P = 0.868) respectively; and SMDs were -0.079 (95%CI:[ -0.169, 0.011], P = 0.086) and -0.097 (95%CI:[ -0.264,0.071], P = 0.258) for IGF-1 and IGFBP-3 respectively. As to the case-control studies, SMDs were 0.568 (95%CI:[ -0.035, 1.171], P = 0.065) and -0.780 (95%CI:[ -1.358, -0.201], P = 0.008) for IGF-1 and IGFBP-3 respectively.
  
  
  CONCLUSIONS
  Inverse association was shown between IGFBP-3 and lung cancer in the case-control studies,and the circulating level of IGFBP-3 underwent a decline during tumorogenesis and development of lung cancer, which suggested IGFBP-3 a promising candidate for the biomarker of lung cancer.
authors.affiliation: Institute of Oncology, Provincial Hospital Affiliated to Shandong University, Shandong University, Jinan, People's Republic of China.
authors.forename: Hongxin
authors.initials: H
authors.lastname: Cao
authors.forename: Guanghui
authors.initials: G
authors.lastname: Wang
authors.forename: Long
authors.initials: L
authors.lastname: Meng
authors.forename: Hongchang
authors.initials: H
authors.lastname: Shen
authors.forename: Zhen
authors.initials: Z
authors.lastname: Feng
authors.forename: Qi
authors.initials: Q
authors.lastname: Liu
authors.forename: Jiajun
authors.initials: J
authors.lastname: Du
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics; D016022:Case-Control Studies; D002471:Cell Transformation, Neoplastic; D056726:Genetic Association Studies; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood / Q000235:genetics; D007334:Insulin-Like Growth Factor I / Q000235:genetics*; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology; D012307:Risk Factors
chemical_list: D014408:Biomarkers, Tumor; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I