Figure 1: Summary of the known roles of LIF in embryo implantation. LIF increases the expression of EGF and implantation genes in receptive endometrium. LIF produced by endometrium and blastocyst regulates growth and development of the embryo. Meanwhile, LIF stimulates stromal decidualization by increasing the production of cytokines and prostaglandins. LIF is also involved in enhancing embryo-endometrial interaction through pinopodes and adhesion molecules. LIF stimulates trophoblast cells differentiation and increase trophoblast capability to invade the uterine stroma. Finally, LIF is involved in recruitment of specific cohort of leucocytes which participates in inflammatory response during implantation. LIF: leukemia inhibitory factor, HB-EGF: heparin binding-epidermal growth factor, Ereg: epiregulin, Ar: amphiregulin, E2: estrogen, P4: progesterone, IL: interleukins, PGs: prostaglandins, COX: cyclo-oxygenase, NK: natural killer, PPAR: peroxisome proliferator-activated receptor, PGE2: prostaglandins E2, hCG: human chorionic gonadotrophin, MUC: mucin, JAM: junctional adhesion molecules.