The NF-кB pathway regulates the expression of over 150 target genes, e.g., cytokines, chemokines, leukocyte adhesion molecules and inducible effector enzymes.  Consequently, it plays a crucial role in innate and adaptive immune responses, inflammatory response, stress responses, apoptosis and so on.  IкB kinase (IKK) is the key of this pathway, and it owns a special structure which consists of catalytic subunit and regulatory subunit.  Naturally, the activation of IKK needs the interaction of the two subunits and phosphorylation by its upstream kinases.  Actually, there are two methods of activation of the NF-кB pathway, and both of the methods need the IKK complex.  Given to the crucial role of IKK, researchers have isolated and synthesized amounts of IKK inhibitors, and these provide a great convenience to develop novel anti-inflammatory and anti-tumor drugs.