RAG2 and neoplasm: For xenograft studies, we implanted tumor pieces (∼2–3 mm3) at three different anatomical sites [14], i.e., subcutis (s.c), kidney capsule (KC), or anterior prostate (AP) in one of the three immunodeficient mouse strains, i.e., NOD/SCID, Rag2−/−, or NOD/SCID-IL2Rγ−/− (NSG) mice.