Association of Polymorphism rs198977 in Human Kallikrein-2 Gene (KLK2) with Susceptibility of Prostate Cancer: A Meta-Analysis

OBJECTIVES: To assess the association of polymorphism rs198977 in the human kallikrein-2 gene (KLK2) and risk of prostate cancer (PCa). METHODS: Two investigators independently searched the PubMed, Elsevier, EMBASE, Web of Science, Wiley Online Library and Chinese National Knowledge Infrastructure (CNKI). Pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for rs198977 and PCa were calculated in a fixed-effects model (the Mantel-Haenszel method) and a random-effects model (the DerSimonian and Laird method) when appropriate. RESULTS: Six studies met the inclusion criteria in this meta-analysis, which included 5859 PCa cases and 4867 controls. Overall, rs198977 was associated with the PCa risk (TT+CT vs. CC, pooled OR = 1.163, 95% CI = 1.076–1.258, P-value <0.0001). When stratified by ethnicity, significant association was observed in Caucasian samples under both allele comparison (T vs. C, pooled OR = 1.152, 95% CI = 1.079–1.229, P-value <0.0001) and dominant model (TT+CT vs. CC, pooled OR = 1.197, 95% CI = 1.104–1.297, P-value <0.0001). In the overall analysis, a comparably significant increase in the frequency of allele T for rs198977 was detected between cases and controls in Caucasian. CONCLUSION: This meta-analysis suggests that rs198977 of KLK2 was associated with susceptibility of PCa in Caucasian and the allele T might increase the risk of PCa in Caucasian.