Theoretical Considerations in Using Animal Models of Metastasis and Brief Methodology for In Vivo Colorectal Cancer Models in SCID and Nude Mice

Metastatic spread is generally responsible for the mortality of colorectal cancer patients. There are no adequate treatments for advanced colorectal cancer, and novel therapeutic modalities are urgently required. To this end, valid metastatic models, which accurately mimic the disease process, are needed. When deciding upon a metastasis model, the goals of the investigation will dictate the complexity of the model chosen. If biological mechanisms are being investigated, only a small number of experimental animals may be required, and a more complex, surgically intensive model may be used. If a therapeutic agent is being evaluated, owing to group sizes required to generate statistically significant effects, a less complex, less surgically intensive model may be preferable. The latter, however, may encompass only a particular phase of metastasis rather than reflecting all aspects of the metastatic cascade.