NFKB1 and B-cell chronic lymphocytic leukemia: Bone marrow stroma cells, nurse-like cells, and T cells produce chemokines and cytokines that activate Btk, which subsequently activates downstream survival signaling, including extracellular-signal-regulated kinases 1/2 (ERK 1/2), phosphoinositide-3-kinases (PI3K), TNF-a and NF-κB pathway that are constitutively activated in CLL cells and this leads to the transcription and overexpression of key anti-apoptotic proteins [201–203].