NF-κB (Nuclear Factor kappa B) is a nuclear transcription factor found in all cell types and is involved in cellular responses to stimuli such as stress, cytokines, free radicals, ultraviolet irradiation, and bacterial or viral antigens. NF-κB plays a key role in regulating the immune response to infection. Consistent with this role, incorrect regulation of NF-κB has been linked to cancer, inflammatory and autoimmune diseases, septic shock, viral infection and improper immune development. There are five members in the NF-κB family: NF-κB1, NF-κB2, RelA (also named p65), RelB, and c- Rel. The most common form of NF-κB is the p50/RelA heterodimer, although other forms of NF-κB dimers, such as p50/p50, p52/p52, p52/RelA, p50/c-Rel, c-Rel/c-Rel, p52/RelB, and p50/RelB, have also been identified in some types of cells. The primary role of NF-κB is to maintain normal cellular functions that range from cell-to-cell communication to cell motility, cell cycle progression, and cell lineage development. The activity of NF-κB is tightly regulated by interaction with inhibitory IκB proteins.