Expression of chemokine receptor CXCR7 in colorectal carcinoma and its prognostic significance.

Previous studies have shown that chemokine receptor CXCR7 plays critical roles in tumor development. However, the clinicopathological and prognostic significance of CXCR7 in colorectal carcinoma (CRC) has not been fully understood. The aim of our study is to investigate the expression of CXCR7 and its clinical significance in CRC. First, quantitative RT-PCR and Western blot assays were performed to determine the expression of CXCR7 mRNA and protein in 20 paired of CRC tissues and corresponding adjacent non-tumor tissues. Next, immunohistochemistry was performed to detect the expression of CXCR7 protein in another 96 cases of CRC tissues, and analyze its correlation with clinicopathological factors of patients. Finally, the correlation of CXCR7 with 5-year overall survival (OS) and progression free survival (PFS) was statistically analyzed by the Kaplan-Meier method and Cox proportional hazards model. Results showed that the expression levels of CXCR7 mRNA and protein were significantly higher in CRC tissues than in normal tissues. Positive CXCR7 expression was observed to be significantly correlated with lymph nodal metastasis (P < 0.001), distant metastasis (P = 0.017), and advanced TNM stage (P < 0.001). Patients with positive expression of CXCR7 were demonstrated to be associated with worse OS and PFS (P < 0.001, P < 0.001, respectively). Moreover, multivariate survival analysis revealed that CXCR7 expression level might be an independent predictive factor for OS and PFS of CRC patients. Collectively, positive CXCR7 expression in CRC was correlated with tumor development and poor prognosis of patients.