title: Type IV collagen as a tumour marker for colorectal liver metastases.
abstract: BACKGROUND
  About 50% of patients with primary colorectal cancer (CRC) will develop liver metastases (CLM). Currently, carcinoembryonic antigen (CEA) is the most common tumour marker for CRC and CLM. However, the sensitivity and specificity of this marker is not optimal, as almost 50% of patients have tumours that do not produce CEA. Therefore there is a need for better markers for CRC and CLM.
  
  
  METHODS
  The circulating levels of type IV collagen were measured in patients with CLM, primary CRC and in healthy controls. The expression pattern of type IV collagen was studied by immunofluorescence in CLM and normal liver tissue. The metastatic volume of CLM in the liver was estimated from CT.
  
  
  RESULTS
  In CLM tissue type IV collagen is highly expressed in the areas of desmoplasia. Patients with primary CRC (Dukes' A-C) did not show any increase in circulating type IV collagen compared to healthy controls. However, patients with CLM have significantly elevated levels of circulating type IV collagen when compared to patients with primary CRC and healthy controls. The levels of type IV collagen decreased during chemotherapy and increased at the time of disease progression. The circulating levels of type IV collagen seem to reflect the tumour burden in the liver.
  
  
  CONCLUSIONS
  Type IV collagen has the potential to be used as tumour associated biomarker for CLM. These results indicate the importance of interaction between cancer cells and the stroma in the tumour microenvironment.
authors.affiliation: Department of Surgical and Perioperative Sciences, Surgery, Umeå University Hospital, Umeå SE-901 85, Sweden.
authors.forename: H
authors.initials: H
authors.lastname: Nyström
authors.forename: P
authors.initials: P
authors.lastname: Naredi
authors.forename: L
authors.initials: L
authors.lastname: Hafström
authors.forename: M
authors.initials: M
authors.lastname: Sund
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000494:pharmacology / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood*; D002272:Carcinoembryonic Antigen / Q000097:blood; D024141:Collagen Type IV / Q000097:blood* / Q000187:drug effects; D015179:Colorectal Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology*; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D002955:Leucovorin / Q000008:administration & dosage; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000097:blood* / Q000188:drug therapy / Q000473:pathology / Q000556:secondary*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D047368:Tumor Burden
chemical_list: D014408:Biomarkers, Tumor; D002272:Carcinoembryonic Antigen; D024141:Collagen Type IV; D002955:Leucovorin; D005472:Fluorouracil