IGF-I and IGFBP-3 and the risk of lung cancer: A meta-analysis based on nested case-control studies

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 similar to 1.13,) and -3.04(95% CI: -7.10 similar to 1.02, P = 0.14), respectively. For IGFBP-3, the pooled OR and WMD were 0.68(95% CI: 0.48 similar to 0.88,) and -112.28(95% CI:-165.88 similar to-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.