title: Ectopic expression of the chemokine CXCL17 in colon cancer cells.
abstract: BACKGROUND
  The novel chemokine CXCL17 acts as chemoattractant for monocytes, macrophages and dendritic cells. CXCL17 also has a role in angiogenesis of importance for tumour development.
  
  
  METHODS
  Expression of CXCL17, CXCL10, CXCL9 and CCL2 was assessed in primary colon cancer tumours, colon carcinoma cell lines and normal colon tissue at mRNA and protein levels by real-time qRT-PCR, immunohistochemistry, two-colour immunofluorescence and immunomorphometry.
  
  
  RESULTS
  CXCL17 mRNA was expressed at 8000 times higher levels in primary tumours than in normal colon (P < 0.0001). CXCL17 protein was seen in 17.2% of cells in tumours as compared with 0.07% in normal colon (P = 0.0002). CXCL10, CXCL9 and CCL2 mRNAs were elevated in tumours but did not reach the levels of CXCL17. CXCL17 and CCL2 mRNA levels were significantly correlated in tumours. Concordant with the mRNA results, CXCL10- and CXCL9-positive cells were detected in tumour tissue, but at significantly lower numbers than CXCL17. Two-colour immunofluorescence and single-colour staining of consecutive sections for CXCL17 and the epithelial cell markers carcinoembryonic antigen and BerEP4 demonstrated that colon carcinoma tumour cells indeed expressed CXCL17.
  
  
  CONCLUSIONS
  CXCL17 is ectopically expressed in primary colon cancer tumours. As CXCL17 enhances angiogenesis and attracts immune cells, its expression could be informative for prognosis in colon cancer patients.
authors.affiliation: Department of Clinical Microbiology, Section of Immunology, Umeå University, SE-90185 Umeå, Sweden.
authors.forename: Lina
authors.initials: L
authors.lastname: Ohlsson
authors.affiliation: Department of Clinical Microbiology, Section of Immunology, Umeå University, SE-90185 Umeå, Sweden.
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Hammarström
authors.affiliation: Department of Surgery, Helsingborg Hospital, SE-25187 Helsingborg, Sweden.
authors.forename: Gudrun
authors.initials: G
authors.lastname: Lindmark
authors.affiliation: Department of Clinical Microbiology, Section of Immunology, Umeå University, SE-90185 Umeå, Sweden.
authors.forename: Sten
authors.initials: S
authors.lastname: Hammarström
authors.affiliation: Department of Radiation Sciences, Section of Oncology, Umeå University, SE-90185 Umeå, Sweden.
authors.forename: Basel
authors.initials: B
authors.lastname: Sitohy
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D018938:Caco-2 Cells; D045744:Cell Line, Tumor; D018932:Chemokine CCL2 / Q000096:biosynthesis / Q000235:genetics; D054357:Chemokine CXCL10 / Q000096:biosynthesis / Q000235:genetics; D054370:Chemokine CXCL9 / Q000096:biosynthesis / Q000235:genetics; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics; D019743:Chemokines, CXC; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005455:Fluorescent Antibody Technique; D019073:HT29 Cells; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; C111835:CCL2 protein, human; C114753:CXCL10 protein, human; C508524:CXCL17 protein, human; C080810:CXCL9 protein, human; D018932:Chemokine CCL2; D054357:Chemokine CXCL10; D054370:Chemokine CXCL9; D018925:Chemokines; D019743:Chemokines, CXC; D012333:RNA, Messenger