Glycosyltransferase and glycosidase activities in ovarian cancer patients

In order to elucidate the mechanism of appearance of abnormal glycoproteins in cancer, activities of glycoprotein glycosyltransferases and glycosidases were determined in the homogenates prepared from normal ovaries and ovarian epithelial adenocarcinoma. Significantly high activities (more than normal mean + 2 S.D.) of these enzymes were found as follows: galactosyltransferase and sialytransferase in 100%; fucosyltransferase 1 (exogenous acceptor, fetuin minus sialic acid and galactose) in 86%; fucosyltransferase 2 (fetuin minus sialic acid, acceptor) in 45%; N-acetylglucosaminyltransferase 1 (ovalbumin acceptor) in 53%; N-acetylglucosaminyltransferase 2 (ribonuclease A as acceptor) in 10% of the samples analyzed. Among the glycosidases, substantially elevated activities above normal controls were found as follows: N-acetyl-beta-D-glucosaminidase in 85%; N-acetyl-beta-D-galactosaminidase in 63%; N-acetyl-beta-D-galactosidase in 50%, and those of alpha-L-fucosidase in 35% of the tumors. In serum of these cancer patients, only levels of galactosyltransferase were consistently elevated compared to controls. Increases in serum levels for other transferases were as follows: fucosyl-1, 10%; fucosyl-2, 60%; sialyl-, 20%; N-acetylglucosaminyl-1, 90%; N-acetylglycosaminyl-2, in 80% of the serum samples from ovarian carcinoma patients. Galactosyltransferase thus appears to be an excellent marker for ovarian carcinoma.