ABCB1 and cancer: We also demonstrated a doxorubicin-induced increase in FOXO3a methylation at arginine residues and increased FOXO3a translocation from the nucleus to the cytoplasm, which sheds light on how FOXO3a regulates ABCB1. Interestingly, complimentary activation of MRP1 has been observed in FOXO3a overexpressing cells, depicting that the regulation of P-gp amended by FOXO3a influences MRP1 as an adjoining factor in conferring cross-resistance in PTX-resistant cancer cells.