Possible limitations of our meta-analysis includes relatively small number of studies, different heterogeneous matching factors, different countries and ethnicities, possible publication
bias, as well as possible interaction with other biologic and environmental factors. It is well documented that ethnic factor contributes to the lung cancer FK228 in vitro incidence. In our study, we included 2 U.S., 1 Chinese, 1 Japanese, 1 Finnish and 1 British studies. Therefore, heterogeneity by ethnicity needs to be taken into account when interpreting our data. Heterogeneous matching factors and differential adjustment for confounding factors are other sources of bias. The above limitations might have contributed to the low statistical power of our meta-analysis. Despite Selleck I-BET151 some limitations, our results based on nested case-control studies which represent of best study design. In addition, we obtained the results from dichotomous and continuous variable respectively, which made the results
more reliable. What’s more, heterogeneity and publication bias of the studies were not significant. Thus, the data of our study are reliability. Conclusion In summary, we found that association between circulating levels of IGF-I, IGFBP-3 and the risk of lung cancer are marginally and statistically significant, respectively. So it may be helpful in the diagnosis and treatment of lung cancer. Since circulating IGF-I and IGFBP-3 remain important factors in lung cancer, more studies SB202190 cost need to be conducted to discern this association. And uniform adjustment of confounding factors across the studies will help in terms of interpretability and comparability. References 1. Spiro SG, Silvestri GA: One hundred years of lung cancer. Am J Respir Crit Care Med 2005, 172: 523–529.CrossRefPubMed 2. Chan JM, Stampfer MJ, Giovannucci E, Gann PH, Ma J, Wilkinson P, Hennekens CH, Pollak M: a prospective study. Science 1998, 279: 563–566.CrossRefPubMed 3. Hankinson SE, Willett WC, Colditz GA, Hunter DJ, Michaud DS, Deroo B, Rosner B, Speizer FE, Pollak M: Circulating concentrations of insulin-like growth factor-I and risk of breast cancer. Lancet 1998,
351: 1393–1396.CrossRefPubMed 4. Ma J, Pollak MN, Giovannucci E, Chan JM, Tao Y, Hennekens CH, Stampfer MJ: Prospective Abiraterone study of colorectal cancer risk in men and plasma levels of insulin-like growth factor (IGF)-I and IGF-binding protein-3. J Natl Cancer Inst 1999, 91: 620–625.CrossRefPubMed 5. Yu H, Spitz MR, Mistry J, Gu J, Hong WK, Wu X: Plasma levels of insulin-like growth factor-I and lung cancer risk: a case-control analysis. J Natl Cancer Inst 1999, 91: 151–156.CrossRefPubMed 6. Yu H, Rohan T: Role of the insulin-like growth factor family in cancer development and progression. J Natl Cancer Inst 2000, 92: 1472–1489.CrossRefPubMed 7. Giovannucci E: Insulin, insulin-like growth factors and colon cancer: a review of the evidence. J Nutr. 2001, 131 (11 Suppl) : S3109-S3120. 8.