A group of proteins that help control many functions in a cell, including cell growth and survival. These proteins also control the body’s immune and inflammatory responses. Nuclear factor-kappa B may be overactive or found in higher than normal amounts in some types of cancer cells. This may lead to cancer cell growth. High levels or overactivity of nuclear factor-kappa B may also lead to inflammatory disorders, such as asthma and ulcerative colitis, and autoimmune disorders, such as rheumatoid arthritis. Also called NF-kappa B and NF-kB.