However, resistant-CLL cells are unable to associate with one another to form a riptosome complex, despite degradation of cIAP1/2 by SMAC mimetic to induce TNF-α production and the presence of RIPK1, FADD, FLICE-like inhibitory protein and caspase-8 [139]. This evidence concerns the gene BIRC2 and B-cell chronic lymphocytic leukemia.