To this end, we compared papilloma incidence between RAG2−/−/IL-4Rα−/− double-knockout mice and RAG2−/−/IL-4Rα+/− mice (Fig. 4A) as well as papilloma incidence between RAG2−/−/IL-4Rα−/− mice and RAG2+/+/IL-4Rα−/− mice (Fig. 4B) after DMBA/TPA treatment. Here, RAG2 is linked to papilloma.