MDM2 309T>G Polymorphism and Risk of Squamous Cell Carcinomas of Head and Neck: a Meta-analysis

Purpose: Several studies have reported influence of the murine double minute 2 (MDM2) 309T>G polymorphism on head and neck squamous cell carcinoma (HNSCC) susceptibility. However, the results remain controversial and ambiguous. We therefore carried out a meta-analysis to explore more precisely the association between MDM2 309T>G variants and the risk of HNSCC.
Methods: Studies on the association between MDM2 309T>G polymorphism and HNSCC were searched in the PubMed database. All relevant studies that met the inclusion criteria were eligible for the analysis. Four genetic models and generalized odds ratios (ORs) and 95% confidence interval (CIs) were used for the assessment.
Results: A total of seven articles with 1,629 cases and 2,472 controls were included in our meta-analysis. Overall, significant associations between the MDM2 SNP309T>G and HNSCC risk for TG vs. TT model and the dominant model (TG+GG vs. TT) were observed (OR=0.82, 95%CI=0.70-0.96 and OR=0.83, 95%CI=0.71-0.96, respectively). On subgroup meta-analysis by ethnicity, a negative association was shown in the Caucasian subgroup (for GG vs. TT: OR=0.661, 95%CI=0.455-0.960; for TG vs. TT: OR=0.653, 95%CI=0.496-0.859; for the dominant model GG+TG vs. TT: OR= 0.657, 95%CI=0.463-0.931). However, in the Asian population no significant association was found. Subgroup analysis by the source of controls also yielded non-significant results. None of the results were materially altered in any genetic model after studies which did not fulfill Hardy-Weinberg equilibrium were excluded.
Conclusion: The present meta-analysis suggested that the MDM2 SNP309 G allele probably acts as an important HNSCC protective factor in Caucasians, but no association exists in Asians.