Quercetin has been reported to kill many types of cancer cells, including human breast cancer MCF-7 cells (114), NSCLC A549 cells (115), ovarian cancer cells (116), etc. Quercetin is able to block the function and expression of ABCB1 and ABCC1, ABCC2 (112, 117, 118). Here, ABCB1 is linked to breast cancer.