[Association of CXCR4 and SDF-1alpha with organ-specific metastasis of nasopharyngeal carcinoma].

OBJECTIVE: To explore the role of CXCR4/SDF-1alpha axis in organ-specific metastasis of nasopharyngeal carcinoma (NPC) by assessment of CXCR4 expression in NPC cells and SDF-1alpha expression in distant target organs of NPC.

METHODS: Thirty patients with NPC and fifteen normal subjects were recruited in this study. The expressions of CXCR4 in NPC and normal cases were identified by RT-PCR and immunohistochemistry (IHC), then the relationship between CXCR4 expression and clinicopathological factors was analyzed. IHC was also used to analyze the SDF-1alpha protein expression in normal cervical lymph nodes (including normal superior and inferior deep cervical lymph nodes), bone marrow, lung, liver, kidney and colon tissues of NPC patients (5 cases/each group).

RESULTS: The relative expression level of CXCR4 mRNA in NPC (0.71 +/- 0.22) was significantly higher than that of normal nasopharynx tissues (0.14 +/- 0.07, F = 27.94, P < 0.05). The relative expression level of CXCR4 protein in NPC (1.58 +/- 0.59) was significantly higher than that of normal nasopharynx tissues (0.51 +/- 0.22, F = 17.75, P < 0.05). The high expression levels of CXCR4 mRNA and protein in NPC were closely related to clinical stage, cervical lymph node metastasis and cancer cell differentiation (P < 0.05). SDF-1alpha protein was strongly expressed in normal superior deep cervical lymph nodes, bone marrow, lung and liver (2.35 +/- 0.67), but absent or very poor expression in inferior deep cervical lymph nodes, kidney and colon tissues (0.68 +/- 0.23), and the differences between them were statistically significant (t = 10.13, P < 0.01).

CONCLUSION: CXCR4 is closely correlated to metastasis of nasopharyngeal carcinoma. CXCR4/SDF-1alpha axis may play an important role in organ-specific metastasis of NPC.