Tissue Expression and Prognostic Role of CXCL12 and CXCR4 in High-grade Serous Ovarian Carcinoma

Abstract

Background/aim: The complex of C-X-C motif chemokine receptor 4 (CXCR4) and its ligand, C-X-C motif chemokine ligand 12 (CXCL12), plays an essential role in cancer cell proliferation, invasion, and metastasis. These are emerging therapeutic targets, and recent studies have reported that inhibition of CXCL12-CXCR4 signaling pathway enhances the effects of immune checkpoint inhibitors. Thus, we aimed to investigate tissue expression of CXCL12 and CXCR4 in high-grade serous ovarian carcinoma (HGSOC) and to determine their potential as prognostic markers.

Patients and methods: We used chemotherapy-naïve, formalin-fixed paraffin-embedded primary ovarian cancer tissues obtained from patients with advanced-stage HGSOC at the time of primary cytoreductive surgery. After histological reassessment, we constructed a tissue microarray and performed immunohistochemical staining for CXCL12 and CXCR4. Thereafter, clinicopathological characteristics and survival outcomes were compared between the high- and low-expression groups.

Results: A total of 97 patients with FIGO stage IIIC-IV HGSOC were included: 15 (15.5%), 66 (68.0%), and 13 (13.4%) patients showed high expression of CXCL12, CXCR4, and both, respectively. The expression level of each protein was not associated with germline BRCA1/2 mutational status, FIGO stage, or residual tumor after primary cytoreductive surgery. In multivariate analysis adjusted for confounders, high CXCL12 expression was identified as an independent poor prognostic biomarker for progression-free survival (adjusted hazards ratio, 1.990; 95% confidence interval=1.090-3.633; p=0.025). However, CXCR4 expression was not associated with patient survival outcomes.

Conclusion: The CXCL12 expression level may represent a prognostic biomarker for HGSOC. Proteins related to the CXCL12/CXCR4 complex may serve as therapeutic targets in HGSOC treatment.

Keywords: CXCR4 receptor; Ovarian cancer; biomarkers; chemokine CXCL12; immunohistochemistry; prognosis.