The PD-1 rs36084323 A > G polymorphism decrease cancer risk in Asian: A meta-analysis

The rs36084323 A > G polymorphism in programmed cell death-1(PD-1) gene has been reported to be associated with cancer risk. However, the results of previous studies were inconsistent. Therefore, we performed a meta-analysis to identify the potential association, by searching the PubMed, EMBASE, Cochrane Library, and the Chinese CNKI, WANFANG and CBM databases. Data were extracted and odds ratios (ORs) with 95% confidence intervals (CIs) were estimated to assess the strength of the association. A total of 10 relevant studies involving 4445 cancer cases and 5126 controls were recruited. Overall, the results indicated that the PD-1 rs36084323 A > G polymorphism was not statistically associated with cancer risk. However, stratified analysis revealed that there was a statistically reduced cancer risk in Asians(G vs. A, OR = 0.89, 95%CI:0.81-0.97, P = 0.008, I² = 48.8%; GG vs. AA, OR = 0.79, 95% CI:0.66-0.94, P = 0.008, I² = 48.7%; GG/AG vs. AA, OR = 0.87, 95%CI:0.76-0.98, P = 0.017, I² = 34.9%; GG vs. AG/AA, OR = 0.85, 95%CI:0.75-0.97, P = 0.027, I² = 40%) and in the patients with EOC(AG vs. AA, OR = 0.69, 95%CI:0.54-0.90, P = 0.005, I² = 0%; GG/AG vs. AA, OR = 0.67, 95%CI:0.52-0.85, P = 0.001, I² = 0). Meta-regression showed that ethnicity (P = 0.029) but not cancer types (P = 0.792), source of controls (P = 0.207) or ample size (P = 0.585) were the sources of heterogeneity. This meta-analysis demonstrates the PD-1 rs36084323 A > G polymorphism is associated with decreased cancer risk in Asian, and suggests it could potentially serve as a biomarker to screen high-risk individuals. Large-scale and well-designed case-control studies are needed to enrich the evidence of this result.