title: Development of a reliable colorectal cancer liver metastasis model.
abstract: The liver is the most frequent and most fatal site of distant spread of colorectal cancer. Most current animal models of liver metastases utilize direct liver or intravascular injection (dissimilar to mechanisms of metastasis) or immunosuppression to establish metastases.
  
  
  OBJECTIVE
  The aim of this study was to develop a reliable rat model of liver metastases in immunocompetent hosts, whereby metastases spread hematogenously as in colorectal cancer.
  
  
  METHODS
  WB-2054 is a poorly differentiated colon adenocarcinoma induced by 1,2 DMH in a WF x BN F1 hybrid rat. WB-2054-M0, Ml, M2, M3, and M4 are successive metastatic variant cell lines obtained through serial application of the Fidler hypothesis. WF x BN F1 rats were inoculated intrasplenically with 1 x 10(6)(M0) or 5 x 10(6)(M0-M4) cells; the spleen was left intact. Animals were evaluated 4 to 12 weeks postinjection and, if no metastases were found, reexplored 1-2 weeks later. Animals with liver metastases were sacrificed, and full abdominal and thoracic zoopsy was performed. Livers were excised and serially sectioned, to determine size, number, and location of liver metastases, and studied histologically to confirm the nature of the metastases.
  
  
  RESULTS
  44% (4/9), 80% (8/10), 86% (65/76), 94% (34/36), and 100% (65/65) of animals inoculated with the M0, M1, M2, M3, and M4 cell lines, respectively, developed liver metastases. Metastases were uniformly spread throughout all lobes of the livers.
  
  
  CONCLUSIONS
  We have developed an extremely hepatotrophic metastatic colorectal cancer cell line. Intrasplenic injection of WB-2054-M4 cells is a reliable model for producing colorectal cancer liver metastases without the need for immunosuppression and should prove valuable in colorectal liver metastasis experiments.
authors.affiliation: Department of General Surgery, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA.
authors.forename: M I
authors.initials: MI
authors.lastname: Brand
authors.forename: S
authors.initials: S
authors.lastname: Casillas
authors.forename: D W
authors.initials: DW
authors.lastname: Dietz
authors.forename: J W
authors.initials: JW
authors.lastname: Milsom
authors.forename: A
authors.initials: A
authors.lastname: Vladisavljevic
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000556:secondary*; D000818:Animals; D015179:Colorectal Neoplasms / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D008113:Liver Neoplasms / Q000473:pathology / Q000556:secondary*; D008297:Male; D009368:Neoplasm Transplantation; D051381:Rats; D011914:Rats, Inbred BN; D011920:Rats, Inbred WF; D014407:Tumor Cells, Cultured