YTHDF2 and breast cancer: m6A‐mediated drug efflux pump ABCB1 overexpression thus causes doxorubicin resistance in breast cancer cells although which writer is causing the modification was not examined in this study.[61] An indirect regulatory role for m6A modification and its reader YTHDF2 on ABCB1 expression was also observed in tamoxifen‐resistant breast cancer cells.