CD40, a member of the tumour necrosis factor receptor superfamily, is expressed by 90–100 % of CLL cells [43], and its activation has been associated with enhanced survival of neoplastic B cells; triggering phosphorylation of ERK 1/2 and upregulating Mcl-1 and Bcl-xl and it may have a role in resistance to chemotherapy [44]. Here, CD40 is linked to B-cell chronic lymphocytic leukemia.