Serum beta-(1----4)-galactosyltransferase activity with synthetic low molecular weight acceptor in human ovarian cancer

A modified procedure was developed for the determination of UDP-galactose: 2-acetamido-2-deoxy-glucopyranoside beta-(1----4)-galactosyltransferase (GT) in human serum which employed the synthetic substrates p-nitrophenyl 6-0-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-beta-D-galactopyranoside and p-nitrophenyl 6-0-(2-acetamido-2-deoxy-beta-D-glucopyranosyl)-alpha-D- mannopyranoside as acceptors. The enzyme products were identified by thin layer chromatography with authentic reference compounds, and the galactosyl linkage was characterized by hydrolysis with beta-D-galactosidase from jack beans. The diagnostic value of this GT for ovarian cancer was tested by measuring the serum enzyme activity in 28 ovarian cancer patients with disease, 20 ovarian cancer patients with no clinical evidence of disease, and 22 healthy females. Although the level of the enzyme activity was significantly higher (P less than 0.002) in the serum of patients with active disease when compared to healthy controls, an appreciable overlap of enzyme activity was found between them. Also, no correlation was found between enzyme activity and tumor size. Differences in methodology and selection of patients makes it difficult to compare results from other reports. However, based on our improved assay procedure, we suggest caution should be exercised in evaluating the merits of GT as a diagnostic marker for ovarian cancer.