THE SERUM LEVEL OF MIDKINE, A HEPARIN-BINDING GROWTH-FACTOR, AS A TUMOR-MARKER

Midkine (MK) is a heparin-binding growth factor distinct from fibrobla st growth factors. Serum levels of MK were determined by enzyme-linked immunoassay using affinity-purified anti-human MK antibody. Elevated levels of MK were frequently observed in sera from patients with vario us carcinomas including lung carcinoma, bile duct carcinoma, colon car cinoma and esophageal carcinoma. Most patients with lung carcinoma sho wed high MK serum values. In colorectal carcinoma, some correlation wa s observed between high MK value and tumor invasion. Surgical removal of carcinomas invariably resulted in decreases in the MK level. Determ ination of serum MK may be useful as an aid in initial screening of ce rtain carcinomas, such as lung carcinoma.