Three strains of IL2rγ-deficient mice, especially receptive to tumor graft, are widely used: NSG/NOG mice (NOD.Prkdcscid.IL2rγnull mice, harboring respectively a complete deletion versus a truncation of the intracellular signaling domain of IL2rγ) and BALB/c.Rag2null.IL2rγnull (BRG) mice. This evidence concerns the gene IL2RG and neoplasm.