Prostate Cancer Risk in Relation to a Single Nucleotide Polymorphism in the Insulin-like Growth Factor-binding Protein-3 (IGFBP3) Gene: a Meta-analysis

Insulin-like growth factor-binding protein-3 (IGFBP3) has been identified as a putative tumor suppressorwith multifunctional roles in the IGF axis. Recently, there have been a growing body of studies investigating therelation between the IGFBP3 A-202C polymorphism, circulating IGFBP3 and prostate cancer risk, but theiroutcomes varied leading to controversy. Hence, it is necessary to perform a meta-analysis covering all eligiblestudies to shed a light on the association of IGFBP3 A-202C and cancer risk. Finally, we included a total of 11relevant articles between 2003 and 2010 covering 14 case-control studies including 9,238 cases and 8,741 controlsfor our analysis. Our results showed that A-202C was a marginal risk factor of prostate cancer (allele contrast:OR=1.08, 95% CI :1.01-1.16; dominant model: OR=1.11, 95% CI :1.01-1.22; heterozygote codominant model:OR=1.11, 95% CI :1.03-1.18; homozygote contrast: OR=1.19, 95% CI :1.03-1.37). Stratification analysis revealedthat sample size and control source were two major heterogeneous meta-factors especially in the recessive model(source: Population-based control group :p=0.30,I2=16.7%, Hospital-based control group: p=0.20, I2=30.3%;sample size: Small: p=0.22,I2= 32.8%, Medium: p=0.09,I2= 48%, Large p=0.60,I2=0.0%); However, contraryto previous findings, no significance was found in racial subgroups. No significant publication bias was foundin our analysis. Considering the robustness of the results and the discrepancy among some studies, there mightbe some unsolved confounding factors, and further more critical large studies are needed for confirmation.