Serum UDP-galactosyl transferase as a potential biomarker for breast carcinoma.
UDP-galactose:N-acetylglucosamine galactosyltransferase (GT) is a membrane-bound enzyme active in the biosynthesis of the carbohydrate moiety of glycoproteins and glycolipids. A soluble form of GT, present in human serum, has recently been found to be elevated in the presence of various neoplasms. In this study, GT levels were measured in randomized serum samples obtained from normal controls (group I, n = 49), patients with benign breast disease (group II, n = 46), disease controls (group III, n = 50), patients with primary breast carcinoma (group IV, n = 53), and untreated metastatic breast cancer (group V, n = 23). Although substantial serum GT elevations were observed in individual control patients with active inflammatory or metabolic diseases, the mean GT levels were significantly higher in the groups with breast carcinoma (P < 0.001, 0.001, 0.02; P < 0.001, 0.001, 0.001 for groups IV and V vs groups, 1, II, and III, respectively). Furthermore, when serum GT levels were correlated with the properative clinical stage of breast cancer, significant elevations were found in 14.3% (3/21) of stage I, 66.7% (8/12) of stage II, 78.6% (11/14) of stage III, and 96.5% (28/29) of stage IV patients. These data indicate that serum GT levels are elevated in the presence of breast carcinoma and that the enzyme elevations correlate positively with the clinical stage of disease. Serum GT may be potentially useful in the detection of recurrent breast carcinoma and as a marker of tumor response to therapy for advanced disease.