Midkine(MK) is a new heparin-binding growth factor,which can promote cell growth/differentiation.Midkine is negatively or lowly expressed in normal tissues,but it is strongly expressed in many carcinoma,its expression upregulation indicates shorten life span and poor prognosis of patients with tumor.therefore midkine maybe utilized as a tumor marker.Apply new molecular biology technology midkine is a candidate molecular target for gene therapy.