Expression of all BCR and of four out of five NF-κB target genes were reduced in CLL cells of the ibrutinib treated mice as compared to control mice (Figure 5a), resulting in a decrease of the BCR and NF-κB gene scores by 61% and 47%, respectively (Figure 5b; P<.05). This evidence concerns the gene NFKB1 and B-cell chronic lymphocytic leukemia.