TNF-a (tumor necrosis factor-alpha, up-regulated 4.0-fold in PBMC and 2.9-fold in lung) is a cytokine secreted mainly by macrophages, which is involved in a wide spectrum of biological processes including cell proliferation, differentiation and apoptosis and has been implicated in a variety of diseases, including autoimmune diseases, insulin resistance, and cancer. The gene discussed is TNF; the disease is cancer.