Interleukin-1, produced mainly by blood monocytes, mediates the panoply of host reactions collectively known as acute phase response. It is identical to endogenous pyrogen. The multiple biologic activities that define IL1 are properties of a 15- to 18-kD protein that is derived from a 30- to 35-kD precursor. Interleukin 1β (IL-1B) is a member of the interleukin 1 cytokine family. It is a pro-inflammatory cytokine against infection, playing an important role in the pathogenesis of cancers. It signals through various adaptor proteins and kinases that lead to activation of numerous downstream targets. The expression level of IL-1B is very low.