NFKB1 and B-cell chronic lymphocytic leukemia: Consequently, we assume that the low CXCR4 expression in tri12 CLL is a manifestation of an activation phenotype or BCR stimulation, linked to the lymphoid microenvironment rather than driven by the tri12 subclone itself, which is also consistent to our recent observation of high active NF-kB in these cells [9].