ABCB1 and cancer: Our results showed that MDR1 3435C > T polymorphism is associated with cancer risk when all studies were pooled together (TT versus CC: OR =1.286, 95% CI =1.123–1.474; CT versus CC: OR = 1.126, 95% CI = 1.020–1.244; dominant model TT + CT versus CC: OR = 1.176, 95% CI = 1.068–1.295; recessive model TT versus CT + CC: OR =1.191, 95% CI =1.065–1.333).