[Significance of serum autotaxin activity in gastrointestinal disease].

Autotaxin (ATX), discovered in human melanoma cells, has been gaining attention because it could be involved in cancer invasion and metastasis as an autocrine motility factor. Recent evidence has indicated that ATX is a key enzyme in the synthesis of lysophosphatidic acid, a lipid mediator with a wide range of biological actions including the stimulation of proliferation and contraction in hepatic stellate cells, a pivotal player in hepatic fibrosis. Serum ATX activity was found to be enhanced in relation to hepatic fibrosis in chronic liver disease due to hepatitis virus C infection, and the possible contribution of ATX to the pathogenesis of hepatic fibrosis should be further clarified. Although an enhanced activity of serum ATX was noted in patients with hepatocellular carcinoma, this may be due to hepatic fibrosis from which hepatocellular carcinoma often arises. It is worth further evaluating whether serum ATX activity is significantly enhanced in patients with cancers of the digestive system other than hepatocellular carcinoma.