title: The prognostic role of serum C-X-C chemokine receptor type 4 in patients with metastatic or recurrent colorectal cancer.
abstract: BACKGROUND
  C-X-C chemokine receptor type 4 (CXCR4) is involved in tumor progression including angiogenesis, metastasis, and survival. However, whether serum CXCR4 levels in metastatic or recurrent colorectal cancer have a prognostic role, have not been evaluated.
  
  
  METHODS
  We analyzed serum samples from 55 patients with advanced colorectal cancer diagnosed between March 2008 and July 2011. Serum CXCR4 levels were quantified by a commercially available enzyme-linked immunosorbent assay (ELISA) kit.
  
  
  RESULTS
  The median age of the patients was 62 years, and all patients received systemic chemotherapy of two or more lines. The median serum CXCR4 level was 283.47 pg/mL (range: 77.48-846.52). Patients with two or more metastatic sites, liver metastasis, or higher CA 19-9 level (>37 IU/mL) showed significantly higher levels of serum CXCR4 than patients without. The median overall survival (OS) of all patients was 19.53 months. OS was significantly longer in patients with lower CXCR4 levels (≤240.45 pg/mL) compared with those having higher CXCR4 levels (>240.45 pg/mL) (median OS: 26.50 vs 17.03 months, P=0.046). Univariate analysis showed that liver metastasis, no palliative surgery, and higher levels of CXCR4 (>240.45 pg/mL) had a significantly poor prognostic value with regard to OS (P<0.05).
  
  
  CONCLUSIONS
  Serum CXCR4 level was positively correlated with metastatic sites, liver metastasis, or higher CA 19-9 level. Also, there was a significant difference in OS according to the level of CXCR4 expression. These findings suggest that serum CXCR4 levels may be a useful surrogate marker of clinical outcome in metastatic or recurrent colorectal cancer.
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Yoon Ji
authors.initials: YJ
authors.lastname: Choi
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Won Jin
authors.initials: WJ
authors.lastname: Chang
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Sang Won
authors.initials: SW
authors.lastname: Shin
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Kyong Hwa
authors.initials: KH
authors.lastname: Park
authors.affiliation: Division of Hematology-Oncology, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
authors.forename: Seung Tae
authors.initials: ST
authors.lastname: Kim
authors.affiliation: Division of Hematology-Oncology, Department of Internal Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Yeul Hong
authors.initials: YH
authors.lastname: Kim
keywords: CXCR4; colorectal cancer; overall survival; prognosis