Orthotopic implantation of colon carcinoma cells provides an experimental model in the rat that replicates the regional spreading pattern of human colorectal cancer

Our goal was to develop an experimental model of colon adenocarcinoma based on the orthotopic implantation of tumour cells in syngenic rats which woul d replicate the pattern of regional spreading of human colorectal adenocarc inoma. We used cell line DHD/K12-PROb and 62 BD-IX rats with intra-caecal i njection of 1 x 10(6) cells. Macroscopic and histological examinations were made at different times after injection (from 1 to 16 weeks) with particul ar emphasis on caecal lesions and rumours were classified according to the TNM system (UICC, 1987). Our results suggest that this model provides a ste p-by-step reproduction of the development of human colorectal adenocarcinom a. It also allows us to predict how long it will take to achieve a certain degree of local spreading, which is essential for the design of cancer-rela ted experiments. Moreover, our model has the advantage that it uses immunoc ompetent rats, which facilitates its application. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.