ESR1 and ovarian cancer: In ERα-positive ovarian cancer, estrogen can not only induce activation of the CXCR7/CXCL11 axis through recruitment of ERα, thus increasing the expression of CXCR7, an estrogen-responsive gene, it can enhance the expression of chemokine ligand I-TAC/CXCL11, which leads to phosphorylation of the CXCR7 promoter site ser-118 and the recruitment of the estrogen receptor ERα, thus realizing positive feedback regulation (40).