To solve this problem, we may need several methodological improvements, e.g. shortening the time required for transportation of the tumor sample from the hospital where patients received surgical resection, using high-grade cancer tissues (i.e. those with greater proliferative potential and resistance to immune attack) or using highly immunodeficient mice, especially NOD-Scid interleukin-2 receptor gamma chain null (NOG/NSG) mice instead of NOD-Scid mice28. This evidence concerns the gene IL2RG and neoplasm.