Association of MDM2 promoter T309G polymorphism with oral cancer risk: A meta-analysis of 3,536 subjects.

The mouse double minute 2 (MDM2) gene is an important regulator of the p53 suppressor gene. To date, evidence concerning the association of the MDM2 single nucleotide polymorphism (SNP) 309T>G (rs2279744) with the risk of developing oral squamous cell carcinoma (OSCC) remains controversial. Therefore, a meta-analysis of all the eligible studies was performed, in order to derive a more precise estimation of this association. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the degree of association in 5 previous studies, including a total of 1,369 OSCC cases and 2,167 controls. The overall analysis revealed a significant association between MDM2 SNP309 and OSCC risk in the heterozygote (TG vs. TT: OR=0.81; 95% CI: 0.68-0.96; P=0.02) and dominant models (TG+GG vs. TT: OR=0.82; 95% CI: 0.69-0.97; P=0.02). The subgroup analysis based on the source of the controls revealed a significant association between population-based controls and the heterozygote model (TG vs. TT: OR=0.75; 95% CI: 0.62-0.91; P=0.004), dominant model (TG+GG vs. TT: OR=0.76; 95% CI: 0.63-0.91; P=0.003) and allele comparison (G vs. T: OR=0.89; 95% CI: 0.79-0.99; P=0.04). Importantly, no evidence of publication bias or obvious heterogeneity were observed in the meta-analysis. The results of the present study demonstrated a decreased risk of developing OSCC for the MDM2 SNP309 group, suggesting MDM2 SNP309 may be a protection-associated genetic variation for OSCC. Additional well-designed studies, with larger sample sizes, are required to further elucidate this association.