CXCR4 and ovarian cancer: In ovarian cancer, estrogen induces CXCR7 expression that promotes tumor cell migration, invasion and epithelial-mesenchymal transition (EMT) through CXCL11 (52) while CXCL12-stimulated EMT depends on CXCR4, suggesting a context-independent contribution of CXCR7 to EMT-signaling (36).