The dietary carotenoid fucoxanthin (FUC) can overcome DOX resistance in breast cancer cells (MCF-7/ADR), hepatocytes (HepG-2/ADR), ovarian cells (Skov-3/ADR) through inhibiting RIF-induced PXR, MDR1, and CYP3A4 expression at both the mRNA level and protein level. This evidence concerns the gene NR1I2 and breast cancer.