Serological studies on CEA, CA 19-9, STn and SLX in colorectal cancer.

BACKGROUND/AIMS: Sialyl Le x (NeuAca2-3Galb1-4(Fucal-3)GlcNAcl-R) (SLX) was introduced as cancer-associated. In this study, serological expression of SLX was examined with that of carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA 19-9) and sialyl Tn antigen (STn) concerning the prognosis and clinicopathological findings of patients with colorectal carcinoma. METHODOLOGY: One hundred and seventeen patients were operated on for colorectal cancer and were enrolled in this study. Serum CEA, CA 19-9, STn and SLX levels were measured pre-operatively by radioimmunoassays and the cut-off values were 5ng/ml, 37U/ml, 45U/ml, and 38U/ml, respectively. RESULTS: Serologically, the positive rates of CEA, CA 19-9, STn and SLX antigens were 33.3, 26.5, 23.1, and 17.1%, respectively. The CEA, CA 19-9 and SLX are stage specific in clinical stage. In the CEA, CA 19-9, STn, SLX-positive patients, 5-year survival rates were 41.0, 29.7, 50.1, and 29.1%, respectively. In the tumor marker-positive patients, prognosis was significantly poorer than in the negative patients. In the patients with Curability A or B, the difference in survival between the SLX-positive and negative patients was significant. Multivariate analysis revealed that significant prognostic indicators were accompanying liver metastasis, histological type, depth of invasion, CEA and SLX. CONCLUSIONS: The combination assay of serum CEA, CA 19-9, STn and SLX will be beneficial for diagnosis and follow-up of colorectal cancer.