We think your discussion on the use of mice with human tumours as cancer models is too pessimistic (Nature 560, 156–157; 2018). These mouse ‘avatars’ can now be armed with human immune cells and are already providing promising insights into immunotherapies (Y. Choi et al. Exp. Mol. Med. 50, 99; 2018).
One example is a personalized mouse model we developed for melanoma. Here, the tumour and immune cells come from the same individual and the response of the mouse to immunotherapy matches that of the patient (see H. Jespersen et al. Nature Commun. 8, 707; 2017).
Difficulties in getting some human grafts to grow successfully in mice could hinder the widespread application of avatar techniques in routine cancer care. Melanoma xenografts are unusual in that they engraft and grow fast enough to support the initiation of immunotherapy in patients. For ethics reasons, however, avatars are better suited to clinical research, for example, to screen patients’ suitability for trials.
Nature 562, 192 (2018)