Association between IL-18 -607 C/A Polymorphism and the Risk of Prostate Cancer: A Meta-Analysis of Case-Control Studies

Abstract

Background: Accumulating evidence shows that cytokines play an important role in the proliferation of prostate cancer. This research is trying to determine that IL-18 -607 C/A polymorphism confers susceptibility to prostate cancer. Methods: Meta-analysis was used to collect data. The relevant studies were identified through a comprehensive search from PubMed, Excerpta Medica Database (EMBASE), Web of Science, and Chinese Biomedical Literature Database (CBM) to obtain related studies published up to December 6, 2017. The association between interleukin (IL)-18 -607 C/A polymorphism and prostate cancer risk was assessed by odds ratios (ORs) together with their 95% confidence intervals (CIs). Results: Nine case-control studies from 6 articles were eventually identified. In the overall population, there is a significant association between IL-18 -607 C/A polymorphism and prostate cancer risk in recessive (CC versus CA/AA: OR = 0.20, 95% CI = 0.15-0.27, P = 0.000) or dominant (CC/CA versus AA:OR = 0.42, 95% CI = 0.30–0.57, P = 0.000) models. In the sub-group analysis according to ethnicity, for Asians, IL-18 -607 C/A polymorphism was significantly associated with prostate cancer in allele contrast (C versus. A: OR=0.82, 95%CI=0.70-0.97, P=0.019), homozygote (CC versus. AA: OR=0.68, 95%CI=0.50-0.92, P=0.013), recessive (CC versus. CA/AA: OR=0.19, 95%CI=0.13-0.27, P=0.000), and dominant (CC/CA versus. AA: OR=0.37, 95%CI=0.28-0.48, P=0.000) models, for Caucasians, IL-18 -607 C/A polymorphism was significantly associated with prostate cancer risk in allele contrast (C versus. A: OR=1.27, 95%CI=1.02-1.58, P=0.033), homozygote (CC versus. AA: OR=1.86, 95%CI=1.19-2.91, P=0.007) and recessive (CC versus. CA/AA: OR=0.25, 95%CI=0.19-0.33, P=0.000) models. Conclusion: This meta-analysis has shown that IL-18 -607 C/A polymorphism contributes to a decreased risk of prostate cancer risk in the Asian population but an increased risk in the Caucasian population.

Keywords: IL-18; Meta-analysis; Polymorphism; Prostate Cancer.

Figure 1

Flow Diagram of Included Studies for This Meta-Analysis

Figure 2.

Forest Plot of IL-18 -607 C/A Polymorphism and Prostate Cancer Risk in Allele Contrast (C versus. A). Group 1 represents Asians; Group 2 represents Caucasians

Figure 3

Forest Plot of IL-18 -607 C/A Polymorphism and Prostate Cancer Risk Under Homozygote Model (CC versus. AA).Group 1 represents Asian; Group 2 represents Caucasians

Figure 4

Forest Plot of IL-18 -607 C/A Polymorphism and Prostate Cancer Risk Under Heterozygote Model (CA versus. AA).Group 1 represents Asian; Group 2 represents Caucasians

Figure 5

Forest Plot of IL-18 -607 C/A Polymorphism and Prostate Cancer Risk Under Recessive Model (CC versus. CA/AA).Group 1 represents Asian; Group 2 represents Caucasians

Figure 6

Forest Plot of IL-18 -607 C/A Polymorphism and Prostate Cancer Risk Under Dominant Model (CC/CA versus. AA).Group 1 represents Asians; Group 2 represents Caucasians

Figure 7

Begg’s Funnel Plot for Publication Bias Test in the Studies of the Meta-Analysis on the Association between IL-18 -607 C/A Polymorphism and Prostate Cancer Risk of the Overall Population (in Allele Contrast C versus. A)