It was reported that the genotype of ABCB1 C1236T (rs1128503) might influence the incidence of breast cancer[28], osteonecrosis[29], and multiple myeloma[30], and the methylation level of the partial ABCB1 gene promoter is closely linked to the efficacy of interventional embolism chemotherapy for cervical cancer[31]. This evidence concerns the gene ABCB1 and breast cancer.