OBJECTIVETo investigate the expression of chemokine receptor CXCR4 in colorectal carcinoma and its relationship with the clinicopathological parameters, and to reveal the role of CXCL12/CXCR4 in the invasion and metastasis of colorectal carcinoma.

METHODSCXCR4 expression was studied in 53 colorectal cancer tissues and 27 normal tissues by immunohistochemistry. Its relationship with clinicopathological characteristics of colorectal cancer patients were analyzed. The CXCR4 expression in tumor and normal specimens and its metastatic sites were assessed by RT-PCR and Western blot.

RESULTSFifty-three colorectal cancer patients,collected from July 2005 to February 2007 in our hospital,were enrolled in this study. CXCR4 was positive in 39 cancer tissue specimens(73.6%) and its high expression rate (in > 50% of cells) was 45.3%. High CXCR4 expression rate was significantly higher in patients with lymph node metastases (N(1)+N(2): 65.4%) than that in those without metastases(N(0) 25.9%). There were also associations between the high CXCR4 expression and the vascular and lymphatic vessel invasions (P<0.01). Meanwhile, there was a rising trend of high expression rate according to American Joint Committee on Cancer (AJCC) stage and pathologic grade,but no significant difference was found(P>0.05). There were no significant correlation of CXCR4 expression with clinicopathological parameters such as tumor location, tumor size, depth of tumor invasion(P>0.05). In addition, the CXCR4 mRNA expression in primary tumor specimens (n=27) from AJCC stage IIII( patients was significantly higher than that in normal tissues. CXCR4 mRNA expression of liver metastasis specimens(n=5) was significantly higher as compared with the primary colorectal cancer specimens(P<0.01).

CONCLUSIONSChemokine receptor CXCR4 is associated with the progression of colorectal carcinoma. High CXCR4 expression is associated with metastasis. The CXCL12-CXCR4 signaling pathway may be a potential novel target of therapy for patients with colorectal cancer.