Nuclear factor NF-kappa-B p100 subunit is a protein encoded by the NFKB2 gene.NFKB has been detected in numerous cell types that express cytokines, chemokines, growth factors, cell adhesion molecules, and some acute phase proteins in health and in various disease states. NFKB is activated by a wide variety of stimuli such as cytokines, oxidant-free radicals, inhaled particles, ultraviolet irradiation, and bacterial or viral products. Inappropriate activation of NF-kappa-B has been linked to inflammatory events associated with autoimmune arthritis, asthma, septic shock, lung fibrosis, glomerulonephritis, atherosclerosis, and AIDS. In contrast, complete and persistent inhibition of NF-kappa-B has been linked directly to apoptosis, inappropriate immune cell development, and delayed cell growth. For reviews, see Chen et al. (1999) and Baldwin (1996).