Evidence to show that the Eph/
ephrin system is involved in
inflammation induced by
infection, injury, inflammatory diseases, and
atherosclerosis has been increased. Although the roles of the Eph/
ephrin system in both neural and vascular development as well as cell motility are well documented, its involvement in inflammatory processes has not yet been elucidated in detail. Moreover, the soluble form of artificially oligomerized or dimerized Fc-fused
ephrin-A1 has been widely used in in vitro and/or in vivo studies to activate the
EphA receptors, whereas its physiological functions as a membrane-anchored
protein remain largely unknown. Recent studies using clinical samples reported that the overexpression of Ephs and
ephrins in some
tumors such as
hepatocellular carcinoma positively correlated with both
malignancy of
tumors and the poor prognosis of
cancer patients. However, the molecular mechanisms underlying
malignancy of
tumors are not fully understood. The author herein summarizes the molecular mechanisms of the Eph/
ephrin system involved in the immune system and inflammatory processes. Especially, the author focuses on
inflammation-induced physiological changes in vascular endothelial cells leading to vascular hyper-permeability and described them in this review. The author also introduces those that contribute to ephrin-A1-mediated lung
metastasis.