TNF-a (also called cachectin), is a major pro inflammatory cytokine, which often rises in parallel with the cytokines interleuking 1 alpha and beta. Both are secreted by macrophages, though tumor necrosis factor alpha (TNFa) is not usually secreted by monocytes. Also like IL-1, TNF-a induces the expression of other autocrine growth factors, increases cellular responsiveness to growth factors and induces proliferation of leukocytes. TNF-a is known to induce upregulation of several nuclear proto-oncogenes as well as of several interleukins predominantly through the NFkB pathway.