The IEG early growth response 1 (EGR1) controls B‐cell proliferation in response to BCR cross‐linking but not after CD40 ligation or TLR4 activation (Gururajan et al., 2008; McMahon and Monroe, 1996) and correlates with survival in CLL (Stratowa et al., 2001). Here, CD40 is linked to B-cell chronic lymphocytic leukemia.