CXCR7 expression in nasopharyngeal carcinoma tissues correlates with disease severity

The chemokine CXCL12 and its receptors, CXCR4 and CXCR7, are important contributors to the pathogenesis of multiple types of tumors. CXCL12/CXCR4 was previously demonstrated to be upregulated in nasopharyngeal carcinoma (NPC) tissues, but the status of CXCR7 in NPC remains unknown. Here, 62 nasopharyngeal carcinoma specimens were obtained from patients who received rhinitis biopsy in our hospital in 2012 and 2013. Another 30 samples were collected from patients with nasopharyngitis who did not have NPC, to serve as a control group. Expression of CXCR7 protein and mRNA in NPC and normal tissues was detected by immunohistochemistry and quantitative real-time polymerase chain reaction, respectively. CXCR7 protein was detected in just 7.1% (2/30) of normal nasopharyngeal samples, but 61.3% (38/62) of tumor tissues (P<0.05). The staining patterns (proportion of stained cells/sample as well as staining intensity) were correlated with lymph node metastasis, TNM staging, and disease severity (P<0.01). Thus, CXCR7 may promote disease progression in nasopharyngeal carcinoma, and may be useful as a predictor of metastasis and prognosis.