ABCB1 and breast cancer: AA increased the activity of the P-gp (P-glycoprotein) energy-dependent efflux pump, which is overexpressed in chemoresistant cancers, without altering the protein expression of P-gp, and thus reversed doxorubicin resistance in breast cancer cells; it also indirectly activated the NF-κB transcription in doxorubicin-resistant breast cancer cells.