title: Aggregated colon cancer cells have a higher metastatic efficiency in the liver compared with nonaggregated cells: an experimental study.
abstract: BACKGROUND
  It remains unclear whether aggregated colon cancer cells have a higher tendency for metastasis formation than nonaggregated cells. Also, the absolute number of cancer cells required for hepatic metastasis remains undefined. The aim of the present study was to compare in the liver the metastatic efficiency of viable nonaggregated colon cancer cells versus cell aggregates for equivalent numbers of cancer cells.
  
  
  METHODS
  DHD/K12/TRb colon cancer cells were administered through the portal vein in syngeneic male BD IX rats. Surgical exploration was performed 8 weeks after injection. Four groups of rats were injected with 0.25 or 0.5 x 10(6) DHD/K12/TRb viable cancer cells, either as single nonaggregated cells or as cell aggregates.
  
  
  RESULTS
  Hepatic metastases were observed in 81% of the rats after intraportal injection of cell aggregates equivalent to 0.5 x 10(6) cancer cells. A significant lower metastatic efficiency was found after the injection of 0.5 x 10(6) non-aggregated, and 0.25 x 10(6) aggregated or nonaggregated cancer cells i.e., 16%, 32%, and 27%, respectively.
  
  
  CONCLUSIONS
  Aggregated colon cancer cells have a higher metastatic efficiency in the liver compared with non-aggregated cells, although a critical number of cancer cells are necessary.
authors.affiliation: Department of Abdominal Surgery, University Hospital Gasthuisberg, Catholic University Leuven, Leuven, Belgium. baki.topal@uz.kuleuven.ac.be
authors.forename: B
authors.initials: B
authors.lastname: Topal
authors.forename: T
authors.initials: T
authors.lastname: Roskams
authors.forename: J
authors.initials: J
authors.lastname: Fevery
authors.forename: F
authors.initials: F
authors.lastname: Penninckx
mesh_terms: D000230:Adenocarcinoma / Q000556:secondary*; D000818:Animals; D002449:Cell Aggregation; D002452:Cell Count; D003110:Colonic Neoplasms / Q000473:pathology*; D008113:Liver Neoplasms / Q000556:secondary*; D008297:Male; D009368:Neoplasm Transplantation; D011169:Portal Vein; D051381:Rats; D011919:Rats, Inbred Strains; D014407:Tumor Cells, Cultured