Human Tumor Xenografts: The Good, the Bad, and the Ugly

There has been a robust discussion for many years now on the utility, or lack thereof, of mouse tumor xenograft models in the study of human cell and gene therapies.[1-4] Of course, the reality is that the value of a model depends on what the modeler is trying to accomplish. A good use of human tumor xenograft models would be to support an experimental hypothesis, a bad use would be to present animal data that add little to the value of in vitro data, and an ugly use of tumor xenografts would be to facilitate publication of a manuscript or give a false sense of safety or efficacy.