CXCR4 and neoplasm: A plausible explanation for this event once again may be linked to NF-κB, where the p50 and p65 subcomplexes bind the CXCR4 gene promoter region and regulate its activation resulting in tumor cell migration.53 Yet, whether NF-κB is directly or indirectly responsible for decreasing CXCR4 in malignant B cells remains to be further studied.