Influence of IGFBP3 Gene Polymorphisms on IGFBP3 Serum Levels and the Risk of Prostate Cancer in Low-risk Korean Men

Abstract

OBJECTIVES To understand the relationship between the -202 A/C single-nucleotide polymorphism (SNP) of the insulin-like growth factor-binding protein 3 (IGFBP3) gene, IGFBP3 serum levels, and risk of prostate cancer (PCa) in a Korean population, as a potential reason for the lower incidence of PCa in the Korean population. METHODS The IGFBP3 levels were measured and the -202 A/C SNP of the IGFBP3 gene was typed for 225 PCa cases and the same number of matched controls. Linear regression analysis and unconditional logistic regression analysis were used to test for the associations between the genotypes and the circulating IGFBP3 levels and the risk of PCa, respectively. To adjust for the potential bias introduced by the hospital cohort, the result of the genotyping was compared with that of 683 community-indwelling healthy men. RESULTS Significantly lower plasma levels of IGFBP3 were noted in the PCa cases. Lower IGFBP3 plasma levels were associated with an increased number of C alleles (P < .001). Compared with the PCa cases, a lower frequency of the C allele was found in the hospital and community controls (P < .05). Compared with AA genotype, logistic regression analysis revealed an increased risk of PCa in subjects who were CC genotype (odds ratio: 2.39, 95% confidence interval: 1.05-5.48). Larger odds (odds ratio: 3.37, 95% confidence interval: 1.35-8.43) for PCa were associated with CC genotype when the analysis was confined to those who had high-risk PCa. CONCLUSIONS The results supported the protective role of -202 A/C SNP of the IGFBP3 gene against PCa in Korean men.