Orthotopic mouse models expressing fluorescent proteins for cancer drug discovery

Importance of the field: Currently used rodent tumor models, including transgenic tumor models, or subcutaneously growing human tumors in immunodeficient mice, do not sufficiently represent clinical cancer, especially with regard to metastasis and drug sensitivity. Areas covered in this review: To obtain clinically accurate models, we have developed the technique of surgical orthotopic implantation (SOI) to transplant histologically intact fragments of human cancer, including tumors taken directly from the patient, to the corresponding organ of immunodeficient rodents. SOI allows the growth and metastatic potential of the transplanted tumors to be expressed and reflects clinical cancer of all types. Effective drugs can be discovered and evaluated in the SOI models utilizing human tumor cell lines and patient tumors. Visualization of many aspects of cancer initiation and progression in vivo has been achieved with fluorescent proteins. Tumors and metastases in the SOI models that express fluorescent proteins can be visualized noninvasively in intact animals, greatly facilitating drug discovery. What the reader will gain: This review will provide information on the imageable mouse models of cancer that are clinically relevant, especially regarding metastasis and their use for drug discovery and evaluation. Take home message: SOI mouse models of cancer reproduce the features of clinical cancer.