CXCR4 and ovarian cancer: To the best of our knowledge, among several studies [22,31,32] describing the crucial role of the CXCR4-CXCL12 axis in ovarian cancer, this is the first prospective study in which the entire axis CXCR4-CXCL12-CXCR7 has been systematically evaluated in epithelial and stromal components, in a representative (n = 308) population of accurately selected stage III-IV ovarian cancer patients with adequate statistical analysis.