ESR1 and breast cancer: In human breast cancer line MCF-7, administration of visfatin, through MAPK and PI3K/Akt signaling pathways, increases the phosphorylation of ERα at serine 118 (Ser118) and 167 (Ser167) residues in vitro and enhances ERE-dependent activity of ER in the presence of 17-β estradiol (E2) [143].