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. EXPERIMENTAL DESIGN: Cell cultures cell line DHD/K12-PROb. ANIMALS BD-IX rats. Tumour implantation intra-caecal injection containing 1 x 10(6) cells in 0.25 ml of PBS. DESIGN: 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). MEASUREMENTS 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.