MDR1 C3435T polymorphism and childhood acute lymphoblastic leukemia susceptibility: An updated meta-analysis

Abstract Background Acute lymphoblastic leukemia (ALL) is the most common malignancy in children, though the etiology of the leukemia is poorly understood, both genetic and environmental factors appear to be involved. Previous studies investigating the association between MDR1 C3435T polymorphisms and risk of children with ALL reported controversial results. Methods We performed a comprehensive meta-analysis to clarify the effect of MDR1 C3435T polymorphisms on risk of childhood ALL. The strength of the association was measured by odds ratio (OR) with 95% confidence interval (CI). Results Nine studies were finally included, involving a total of 1462 cases and 1522 controls. There was no association between MDR1 C3435T polymorphism and children ALL risk in all of four models in overall populations (CT vs. CC: OR = 0.86, 95% CI = 0.65–1.15, P  = 0.310; TT vs. CC: OR = 1.50, 95% CI = 0.96–2.35, P  = 0.076; TT/CT vs. CC: OR = 1.12, 95% CI = 0.95–1.33, P  = 0.166; TT vs. CC/CT: OR = 1.58, 95% CI = 0.97–2.56, P  = 0.067). Subgroup analysis by race suggested that this association existed in Asians under the under the homozygote model and recessive model (TT vs. CC: OR = 2.45, 95% CI = 1.24–4.86, P  = 0.010; TT vs. CT/CC: OR = 2.65, 95% CI = 1.22–5.75, P  = 0.014). Conclusions This meta-analysis suggests there was no association between MDR1 C3435T polymorphism and children ALL risk in overall populations, but significant association with an increased risk in Asians.