The lymphoma-burdened, sick Eμ-Myc;Rag-1-Cre;Mcl-1fl/+ mice showed significantly lower lymph node weights (*P=0.031) and lymphocyte numbers in the peripheral blood (*P=0.046) than sick Eμ-Myc;Rag-1-Cre mice (Figures 4b and c). This evidence concerns the gene RAG1 and lymphoma.