Patient-derived tumor xenografts or PDXs are considered a valuable alternative to patient-derived tumor organoids in faithfully modelling cancer, but a study published online today by the scientific journal Nature Genetics pinpoints unexpected weaknesses of these systems.

Ben-David U, Ha G, Tseng Y, Greenwald NF, Oh C, Shih J, McFarland JM, Wong B, Boehm JS, Beroukhim R & Golub TR. Patient-derived xenografts undergo mouse-specific tumor evolution. Nature Genetics 49, 1567–1575 (2017). doi:10.1038/ng.3967