Mice with a NOD/SCID background with IL2rg mutations, such as NOD.Cg-PrkdcscidIl2rgtm1Wjl (NSG)9 and NODShi.Cg-PrkdcscidIl2rgtm1Sug(NOG) mice10, are able to grow almost all types of human cancers in vivo, including most solid tumors and hematological malignancies, and can be engrafted with functional human immune cells11–14. This evidence concerns the gene CTSG and cancer.