[Elevation of serum fucosyltransferase activities in malignant diseases--a sensitive tumor marker?]

Fucosyltransferase (FT) is considered to be one of the most important glycosyltransferases responsible for the synthesis of cancer-associated carbohydrate chains such as CA19-9 and SLX. To determine whether FT is a sensitive tumor marker, we measured the enzyme activity of FT in sera from 136 cancer patients, 14 patients with benign diseases and 59 healthy controls, by using PA (pyridylamino)-labeled type II biantennary oligosaccharide derived from human serotransferrin as an acceptor substrate. Serum FT activity was significantly elevated in patients with cancer compared to healthy controls. Analysis of the enzyme products using HPLC and various fucosidases with different specificity revealed that alpha 1----3 FT was responsible for most of the elevation of the enzyme activity in sera from cancer patients. It should be stressed that the alpha 1----3FT derived from cancer patients transferred fucose to terminal lactosamine residues of type II biantennary oligosaccharides already attached to sialic acid. This indicates that the substrate specificity is clearly different from that reported in normal sera and tissues. In addition to alpha 1----3FT, some glycosidases including fucosidase were also elevated in sera from cancer patients.