[Specificity and selectivity of the NFkappaB response]

NFKB target genes are very diverse. This transcription factor regulates expression of the genes which are involved in immunity and inflammation, cell proliferation and apoptosis, as well as genes that encode negative regulators of NFkappaB. Detected in the cytoplasm of almost all cell types, NFkappaB is activated in response to several external stimuli, including interleukins, growth factors, viral and bacterial infections, and physical factors (e.g. UV light). Constitutively activated NFkappaB has been associated with many aspects of tumour development, including promoting cancer cell proliferation, preventing apoptosis, and increasing a tumour's angiogenic and metastatic potential. The inhibition of NFkappaB activity, in turn, may affect the induction of genes that are required for immunity. Dimeric NFkappaB proteins, show high specificity and selectivity. This is why not all NFkappaB-dependent genes are expressed in every cell. In this review, specificity and selectivity of the NFkappaB response are presented as a result of a combination of many regulatory mechanisms.