Pre-operative serum levels of sialyl Tn antigen predict liver metastasis and poor prognosis in patients with gastric cancer

Aims: To clarify the prognostic value of preoperative serum levels of sialyl Tn antigen (STN) for survival of gastric cancer patients. Methods: Pre-operative serum levels of STN, sialyl Lewisaantigen (CA19-9) and carcinoembryonic antigen (CEA) were examined in 180 patients who underwent resection of gastric cancer. Patients were divided into high and low antigen groups on the basis of a selected diagnostic-based cut-off value. Correlation between high antigen serum levels, established clinicopathologic factors and prognosis was examined by univariate and multivariate analysis. Results: Twenty-eight patients (15.6%) were classified as high STN; 37 (20.6%) as high CA19-9; and 33 (18.3%) as high CEA. The survival time of the high STN, CA19-9 or CEA group was shorter than that of the respective low-antigen group (P<0.0001, P=0.0008 or P=0.0002, respectively). Patients with stage III/IV tumours with high STN had a shorter survival time that those with low STN (P=0.0004). Cox's regression with multiple covariates showed that high serum STN is an independent factor predicting a worse outcome in gastric cancer patients. Multiple logistic regression analysis revealed that high serum STN is an independent predictor for the development of liver metastasis. Conclusions: Pre-operative high serum levels of STN predict both liver metastasis and poor prognosis after resection for gastric cancer.