CXCR4 expression is associated with lymph-node metastasis of oral squamous cell carcinoma

The support mechanisms that are involved in lymph-node metastasis of oral squamous cell carcinoma (OSCC) remain largely unknown. Recent studies have demonstrated that tumor cells express chemokine receptors and use chemokines to metastasize to the target organ in many malignancies in humans. In this study, we examined the expression and function of chemokines and their receptors in OSCC. The expression of chemokine receptors was assessed in eight OSCC cell lines. CXCR3 mRNA and protein were expressed in all the OSCC cell lines examined, while CXCR4 mRNA and protein were expressed only in HSC2, HSC3, and Ca9-22 cells. Treatment with the ligand for CXCR4, stromal cell-derived factor-1 (SDF-1), enhanced the motility and invasiveness of OSCC cells expressing CXCR4. However, the CXCR3 ligand, Mig, did not affect the migration or invasiveness of CXCR3-positive cells. We also evaluated the clinical significance of CXCR4 expression immunohistochemically. CXCR4 expression was detected in 27 (30%) of the 90 OSCC tissues tested, and was localized in the membrane and cytoplasm of cancer cells. There was a highly significant correlation between CXCR4 expression and lymph-node metastasis (P=0.0035). Collectively, these findings suggest that CXCR4 might be involved in the lymph-node metastasis of OSCC.