Role of CXC chemokine receptor type 7 in carcinogenesis and lymph node metastasis of colon cancer

Upregulated expression of the CXC chemokine receptor type 7 (CXCR7) promotes breast, lung and prostate cancer progression and metastasis. However, the role of CXCR7 in colon cancer has not been determined. We hypothesized that increased CXCR7 expression may contribute to human colon cancer occurrence and progression. Reverse transcription quantitative polymerase chain reaction and western blot analysis were performed on 34 malignant and 18 normal colon tissue specimens. The specimens were obtained from 19 male and 15 female patients, with a mean age of 52 years (range, 34-79 years). Of the 34 patients, 20 had lymph node metastases. None of the patients had received adjuvant radiotherapy or chemotherapy prior to surgery. This study demonstrated that CXCR7 levels were significantly higher in colon tumors compared with those in normal colon tissue (P<0.01). In addition, lymph node metastatic colon tumors exhibited significantly higher CXCR7 expression compared with non-metastatic tumors (P<0.01); however, there were no differences in CXCR7 expression among distinct histopathological types (well-differentiated vs. moderately-to-poorly differentiated adenocarcinoma, P>0.01). Therefore, the evidence obtained from the present study supports involvement of the upregulated CXCR7 expression in colon tumorigenesis and lymph node metastasis.