Sialyl Tn antigen is an independent predictor of outcome in patients with gastric cancer.

The prognostic value of the immunohistochemical expression of Sialyl Tn antigen (STn) was evaluated in 242 patients with gastric carcinoma. Formalin-fixed, paraffin-embedded specimens of gastric adenocarcinomas were stained with the monoclonal antibody C1282, produced by immunization with ovine submaxillary mucin (OSM). Positive immunoreactivity for STn was observed in 149 (62%) patients. The expression of STn did not correlate with stage of disease (TNM), tumour location, presence of lymph-node or distant metastases, histological type, age or gender. STn immunoreactivity correlated strongly with overall survival in univariate analysis. The median survival in the STn-positive group was 21 months, in comparison to 38 months in the STn-negative group. The difference in survival between STn-negative and STn-positive tumours was significant in patients with stage-I cancer, but not in patients with stage-II -III or -IV disease. STn immunoreactivity emerged as an independent prognostic factor in Cox multivariate analysis. It is concluded that the immunohistochemical expression of STn is a good marker in the prediction of survival in patients with stage-I gastric carcinoma.