In hematopoietic cancer cells such as multiple myeloma and adult T-cell leukemia as well as lung cancer cells, either stabilization of the NIK protein through impaired negative regulation by the TRAF3/TRAF2/cIAP complex or aberrant expression of the NIK mRNA have been reported [5], [6], [7], [8]. The gene discussed is TRAF2; the disease is plasma cell myeloma.