To determine if earlier onset of disease could be seen in other lymphoma models, we generated c-rel–/– strains of pEμ-B29-TCL1 (TCL1-Tg) transgenic mice.33 These mice exhibit slower disease progression than in the Eμ-Myc model and in our experiments many mice developed tumours at non-lymphoid sites (not shown). Here, REL is linked to lymphoma.