Leukemia inhibitory factor (LIF) is a pleiotropic glycoprotein, belonging to the IL-6 receptor family. LIF is a 19.7 kDa protein containing 202 amino acid which high expression in human liver, bone, uterus, kidney and the central nervous system. LIF is an inducer of differentiation in M1 leukemia cells, osteoblasts and glia. Not only stimulates proliferation of DA1 cells inhibits proliferation of corticotrophs and promote cell survival in some cell types but also induce apoptosis in others.