Lack of Association between Common Polymorphisms in Selenoprotein P Gene and Susceptibility to Colorectal Cancer, Breast Cancer, and Prostate Cancer: A Meta-Analysis

Background and Objective. Selenoprotein P (SEPP1) is the major selenoprotein in plasma. Previous studies have demonstrated that SEPP1 expression was reduced in human prostate and colon tumors. Nowadays, studies concerning SEPP1 gene polymorphisms and cancer susceptibility have been extensively investigated, whereas results from these studies remain debatable rather than conclusive. Thus, we performed the present meta-analysis to comprehensively assess the association between two common polymorphisms (rs3877899 and rs7579) in SEPP1 and cancer susceptibility. Method. We search the PubMed, Embase, Google Scholar, and Wanfang (China) databases (up to December 1, 2020) to identify all eligible publications. The pooled odds ratio (OR) correspondence with 95% confidence interval (CI) was calculated to evaluate the associations. Results. Finally, nine eligible studies with 7,157 cases and 6,440 controls and five studies with 2,278 cases and 2,821 controls were enrolled in rs3877899 and rs7579 polymorphisms, individually. However, a null significant association was detected between the two polymorphisms in SEPP1 and susceptibility to colorectal, breast, and prostate cancer in all comparison models. Subsequently, subgroup analysis based on tumor type, no significant association was identified for prostate, breast, and colorectal cancer. In addition, when the stratification analyses were conducted by the source of control, HWE status, and ethnicity, yet no significant association was found. Conclusions. The current meta-analysis shows that SEPP1 rs3877899 and rs7579 polymorphisms may not be associated with susceptibility to colon cancer, breast cancer, and prostate cancer, and further well-designed studies with a larger sample size are warranted to validate our findings.