NF-κB induces transcription of a large repertoire of stress-response genes in CLL, including the anti-apoptotic proteins Bcl-2 and Mcl-1 [29], allowing us to speculate that stress-induced activation of PARP, and NF-κB in CLL cells occurs as a mechanism of protecting CLL cells from damage. This evidence concerns the gene NFKB1 and B-cell chronic lymphocytic leukemia.