Lack of Association of the MDR1 C3435T Polymorphism with Susceptibility to Gastric Cancer and Peptic Ulcer: a Systemic Review and Meta-analysis

Background: The multidrug resistance 1 gene (MDR1) C3435T polymorphism has been demonstrated toinfluence the P-glycoprotein (P-gp) activity level which is related to inflammation and carcinogenesis. Thismeta-analysis was performed to estimate the association between the MDR1 C3435T polymorphism and therisk of gastric cancer (GC) and peptic ulcer (PU). Materials and
Methods: A literature search was conductedwith PubMed, Embase and the Cochrane library up to November 2013. Odds ratios (ORs) with 95% confidenceintervals (CIs) were used to assess the strength of association. Data were analyzed using Review Manager (Version5.2), and Stata package (version 12.0) for estimation of publication bias.
Results: Six case-control studies wereincluded, of which five were for GC and two for PU. Overall, no evidence was found for any association betweenthe MDR1 C3435T polymorphism and the susceptibility to GC and PU. In the stratified analysis by H. pyloriinfection status, stage and histology classification of GC, and PU type, there was still no significant associationbetween them.
Conclusions: This meta-analysis suggested that the MDR1 C3435T polymorphism is not associatedwith susceptibility to GC and PU. Large and well-designed studies are warranted to validate our findings.