ABCB1 and breast cancer: miR-451 sensitizes breast cancer cells to doxorubicin via targeting ABCB1.32 Wu et al. found that the methylation of miR-129-5p CpG islands could regulate multidrug resistance in gastric cancer by targeting ABC transporters.33 Let-7 modulates the acquired resistance of ovarian cancer to taxanes via the IMP-1-mediated stabilization of ABCB1.34