title: Colonoscopic injection for murine solid cecal cancer model.
abstract: BACKGROUND
  The validity of current animal colon cancer models is questionable. This study was performed to evaluate whether colonoscopic injection of a murine colon cancer cell line into the cecal wall of immunocompetent rats leads to a solid tumor.
  
  
  METHODS
  A bolus of bowel prep was given to BD-IX rats. Anesthesia was injected intraperitoneally. Video fiberscope allowed for irrigation and suction. Failure was inability to reach/inject cecum. Procedure was performed by four surgeons; 100 μl of colon tumor cell suspension (DHD/K12TRb; 10 million cells in 0.1 ml) was injected into cecal wall with 23-gauge needle placed on 3 mm wire resulting in a blister. Rats were allowed to recover. Solid tumor growth was measured at scheduled necropsy at 4 weeks. Sample size (107 rats: type I error 0.05; power 80%) was based on a pilot study. Data were presented as median (range).
  
  
  RESULTS
  A total of 107 male BD-IX retired breeders weighing 356 g (range 256-432 g) underwent colonoscopy with submucosal injection of cecal wall. A single solid cecal cancer was identified in 98 (91.5%) rats at scheduled necropsy. Histology confirmed adenocarcinoma with tumor size of 4 mm (range 2.6-8.4 mm). Peritoneal carcinomatosis was found in ten (9.3%) rats. Distant metastases were found in three (2.8%) rats. Complications occurred in four (3.8%) rats: two aspirations and two colon perforations.
  
  
  CONCLUSIONS
  A solid cecal tumor without carcinomatosis or metastasis has been developed by colonoscopic injection of a rat colon cancer cell line in 79% of immunocompetent rats.
authors.affiliation: Division of Colon & Rectal Surgery, State University of New York, Academic Office, HSC, T18-046B, Stony Brook, NY 11794-8191, USA.
authors.forename: Joshua R
authors.initials: JR
authors.lastname: Karas
authors.forename: Rahila
authors.initials: R
authors.lastname: Essani
authors.forename: Christopher
authors.initials: C
authors.lastname: Haughn
authors.forename: Miroslav
authors.initials: M
authors.lastname: Uchal
authors.forename: Muath M
authors.initials: MM
authors.lastname: Bishawi
authors.forename: Roberto
authors.initials: R
authors.lastname: Bergamaschi
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000818:Animals; D002430:Cecal Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor / Q000637:transplantation; D003113:Colonoscopy; D005240:Feasibility Studies; D007267:Injections; D008297:Male; D051379:Mice; D009368:Neoplasm Transplantation / Q000379:methods*; D011446:Prospective Studies; D051381:Rats; D014183:Transplantation, Heterologous