Intron 3 Sixteen Base Pairs Duplication Polymorphism of P53 Contributes to Breast Cancer Susceptibility: Evidence from Meta-Analysis

BACKGROUND: P53 is a tumor suppressor gene and plays important role in the etiology of breast cancer. Intron 3 sixteen-bp duplication polymorphism of p53 has been reported to be associated with breast cancer risk. However, the reported results remain conflicting rather than conclusive. METHODS: A meta-analysis including 19 case-control studies was performed to address this issue. Odds ratios (ORs) with 95% confidence intervals (CIs) were adopted to evaluate the association. RESULTS: The overall results suggested that the variant genotypes were associated with a significantly increased breast cancer risk (Del/Ins vs Del/Del: OR = 1.18, 95% CI: 1.00–1.40; Ins/Ins vs Del/Del: OR = 1.42, 95% CI = 1.09–1.84; Ins/Ins+Del/Ins vs Del/Del: OR = 1.21, 95% CI = 1.03–1.41). When stratifying by sample size of studies, a significantly elevated risk was also observed among large sample studies (>500 subjects) but not among small sample studies (≤500 subjects). CONCLUSION: These results suggested that the 16-bp duplication polymorphism of p53 may contribute to susceptibility to breast cancer. Additional well-designed large studies were required to validate this association in different populations.