Expression of the CXCL12/CXCR4 and CXCL16/CXCR6 axes in cervical intraepithelial neoplasia and cervical cancer

Abstract

The chemokine CXCL12 is highly expressed in gynecologic tumors and is widely known to play a biologically relevant role in tumor growth and spread. Recent evidence suggests that CXCL16, a novel chemokine, is overexpressed in inflammation-associated tumors and mediates pro-tumorigenic effects of inflammation in prostate cancer. We therefore analyzed the expression of CXCL12 and CXCL16 and their respective receptors CXCR4 and CXCR6 in cervical intraepithelial neoplasia (CIN) and cervical cancer and further assessed their association with clinicopathologic features and outcomes. Tissue chip technology and immunohistochemistry were used to analyze the expression of CXCL12, CXCR4, CXCL16, and CXCR6 in healthy cervical tissue (21 cases), CIN (65 cases), and cervical carcinoma (60 cases). The association of protein expression with clinicopathologic features and overall survival was analyzed. These four proteins were clearly detected in membrane and cytoplasm of neoplastic epithelial cells, and their distribution and intensity of expression increased as neoplastic lesions progressed through CIN1, CIN2, and CIN3 to invasive cancer. Furthermore, the expression of CXCR4 was associated significantly with the histologic grade of cervical carcinoma, whereas the expression of CXCR6 was associated significantly with lymph node metastasis. In Kaplan-Meier analysis, patients with high CXCR6 expression had significantly shorter overall survival than did those with low CXCR6 expression. The elevated co-expression levels of CXCL12/CXCR4 and CXCL16/CXCR6 in CIN and cervical carcinoma suggest a durative process in cervical carcinoma development. Moreover, CXCR6 may be useful as a biomarker and a valuable prognostic factor for cervical cancer.