Abstract: Midkine (MK) is a new heparin-binding growth factor. It was named after the initial expression of mouse embryonic kidneys in the second trimester of pregnancy. MK is highly expressed in a variety of malignant tumor tissues and plays an important role in the occurrence, development and metastasis of tumors, which can promote the process of cancer cell proliferation, migration and tumor angiogenesis, and affect the prognosis of tumor patients, while its expression is low or even undetectable in normal tissues or adjacent tissues. Significantly, because it is a soluble cytokine, the elevated MK is readily apparent in the blood and other body fluids such as urine and cerebrospinal fluid (CSF), making MK a relatively convenient, accessible, non-invasive and inexpensive biomarker for population screening and early disease detection. MK has already proven to be a biomarker that can significantly improve detection, management and treatment of cancer. This article reviews the research status of MK and tumor development, prognosis and its application in biomarkers.

Key words: neoplasms, cytokines, midkine, development, marker