Journal of Experimental & Clinical Cancer Research Research IGF-I and IGFBP-3 and the risk of lung cancer: A meta-analysis based on nested case-control studies Bo Chen, Shan Liu, Wei Xu, Xueli Wang, Weihong Zhao and Jianqing Wu* BioMed Central Open Access Address: Department of Geriatrics, The First Affiliated Hospital, Nanjing Medical University, Nanjing, PR China Email: Bo Chen - chenbo361du@163.com; Shan Liu - wdqails@sina.com; Wei Xu - ann_xw@hotmail.com; Xueli Wang - wxl- 851204@163.com; Weihong Zhao - zhaoweihong_1@medmail.com.cn; Jianqing Wu* - jwuny@njmu.edu.cn * Corresponding author Published: 24 June 2009 Journal of Experimental & Clinical Cancer Research 2009, 28:89 doi:10.1186/1756-9966-28-89 This article is available from: http://www.jeccr.com/content/28/1/89 Received: 14 May 2009 Accepted: 24 June 2009 © 2009 Chen et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Lung cancer is the leading cause of death from cancer worldwide. Conventional studies mainly think that insulin-like growth factor-I (IGF-I) and IGF-binding protein-3 (IGFBP-3) may promote and inhibit tumor growth, respectively. However, there are many different results about their function in some recent epidemiological studies. To evaluate the relationship between circulating serum levels of IGF-I, IGFBP-3 and lung cancer, a systematic review and meta-analysis of the published data was performed. Methods: Literatures searched on PubMed and Embase databases were enrolled in the Meta- analysis. The Meta-analysis of all eligible studies was applied with Stata 10.0 software, and the pooled odds ratio(OR) and weighted mean difference (WMD) value were obtained. The Q test, Egger's test and Begg's funnel plot were used to evaluate the heterogeneity and publication bias between the studies. Results: There are no statistically significant heterogeneity and publication bias between the studies. For IGF- I, the pooled OR and WMD were 0.87(95%CI: 0.60~1.13,) and -3.04(95%CI: - 7.10~1.02, P = 0.14), respectively. For IGFBP-3, the pooled OR and WMD were 0.68(95%CI: 0.48~0.88,) and -112.28(95%CI: -165.88~-58.68, P < 0.0001), respectively. Conclusion: The association between circulating IGF- I levels and the risk of lung cancer were not statistically significant; IGFBP-3, acts as a tumor suppressor and has a inverse correlation with the risk of lung cancer. Background Lung cancer is the leading cause of death from cancer worldwide, and the care rate remains less than 15% despite improvements in surgery, radiotherapy and chem- otherapy [1]. Insulin-like growth factor-I (IGF-I) and IGF- binding protein-3 (IGFBP-3) have been widely accepted that they may have key role on the genesis and develop- ment of many types of tumor including lung cancer [2-7]. Growth hormone stimulates production of IGF-I in the liver and peripheral tissues. IGF-I is also released locally in response to damage, either directly or through the action of other factors associated with tissue responses to dam- age, including epidermal growth factor, fibroblast growth factor, and platelet-derived growth factor [8]. IGFBP-3 is the dominant circulating binding partner for both IGFs, accounting for 70 to 80% of their blood levels [8,9]. Mul- Page 1 of 6 (page number not for citation purposes)