title: Establishment of an experimental model of colon cancer which replicates the regional extension pattern of human colorectal adenocarcinoma.
abstract: OBJECTIVE
  The aim of this study was to develop an experimental model of colon adenocarcinoma based on the orthotopic implantation of tumor cells in syngenic rats, which reproduces the regional extension pattern of human colorectal adenocarcinoma.
  
  
  METHODS
  Cell cultures: cell line DHD/K12-PROb.
  
  
  METHODS
  BD-IX rats. Tumour implantation: intra-caecal injection containing 1 x 10(6) cells in 0.25 ml of PBS.
  
  
  METHODS
  randomized observation study of three groups until five rats were shown to have cancer implantations in each group: GROUP I: sacrificed one week after the injection (n = 6), GROUP II: sacrificed two weeks after the injection (n = 9), GROUP III: sacrificed four weeks after the injection (n = 10).
  
  
  METHODS
  macroscopic and histological examination, with particular emphasis on caecal lesions. Tumours were classified according to the TNM system (UICC, 1987).
  
  
  RESULTS
  GROUP I: tumors were found in 83% of cases (5/6), 4 of which were classified as T1N0M0 and 1 as T2N0M0. GROUP II: tumour in 55.5% of cases (5/9). One was classified as T1N0M0, 3 as T2N0M0 and 1 as T3N0MPER. GROUP III: tumors were found in 50% of cases (5/10). Two were classified as T4N0M0, 2 as T4N1MPER, and 1 as T3N1MPER. The degree of wall infiltration of the tumor showed statistical differences between groups I and III and groups II and III (p < 0.05).
  
  
  CONCLUSIONS
  Our model offers a step by step reproduction of events described for human colorectal adenocarcinoma. It was therefore easy to predict how long it would take to achieve a degree of local extension, which is essential in the design of cancer experiments. Moreover, this model has the advantage that it uses immunocompetent rats, which facilitates the methodology.
authors.affiliation: Research Unit, Albacete General Hospital.
authors.forename: D
authors.initials: D
authors.lastname: García Olmo
authors.forename: M
authors.initials: M
authors.lastname: García Rivas
authors.forename: D C
authors.initials: DC
authors.lastname: García Olmo
authors.forename: M
authors.initials: M
authors.lastname: Atiénzar
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology*; D000818:Animals; D003110:Colonic Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental; D051381:Rats; D014407:Tumor Cells, Cultured