Serum sialyl-tn antigen level as a prognostic indicator in patients with gastric-cancer

The sialyl-Tn antigen (STN) is a mucin glycoprotein that recently has received attention as a cancer-related antigen. This antigen is considered to be the antigen of core region of mucin oligosaccharides, which differs considerably from type 1 chain carbohydrate antigen 19-9 (CA19-9) and type 2 chain antigen sialyl-SSEA-1 (SLX). In the present study, serum STN levels were measured in patients with gastric cancer in order to determine the clinical significance of STN. The mean STN level in cancer patients was 52.0 U/ml and the rate of positivity was 20.1% (37/184). The mean serum level and the rate of positivity for STN each rose in accordance with increases in histologic stage, degree of lymph node metastasis and depth of invasion. In relation to prognosis, for patients with advanced gastric cancer, the prognosis of patients who were STN-positive was significantly poorer than those who were STN-negative. These results suggest that measurement of serum STN is useful for prediction of the tumor stage and serum level of STN may be a good prognostic indicator for gastric carcinoma.