A recent research demonstrated that 17b-estradiol, tamoxifen, and fulvestrant induce nuclear and nucleolar translocation of HE4 and that HE4 overexpression induces resistance to antiestrogens, resulted in estrogen receptor-α (ER-α) downregulation in vitro and in human ovarian cancers by interacting with it [24]. This evidence concerns the gene ESR1 and ovarian cancer.