RAG2 and neoplasm: On Day 18 after B16F10‐OVA injection, the tumour sizes of Rag2−/−‐OT1‐iT‐treated mice were less than 100 mm2, but those of PBS‐treated tumour‐bearing mice were over 200 mm2 (n = 5, p < 0.001) (Figure 4B), indicating that Rag2−/−‐OT1‐iT cell therapy inhibits tumour growth significantly.