Six monoclonal antibodies reacted with different cancer-associated antigens were studied. In which, CL-2 reacts with carcinoembryonic antigen (CEA), CL-3: CEA and S-Tn, CL-4: glycosphingolipid, PS-7: S-Tn. PS-10: S-Tn Tn, and glycosphingolipid, all weakly, and GS-2: CEA, Tn, S-Tn, glycolipid, all strongly. All of the monoclonal antibodies expressed strongly in gastric cancer tissues, the positive rate are 62%-91.6%, but none are expressed in normal gastric tissues, except PS-7 (35% weakly expressed). The cancer-associated antigens in gastric juice, serum and feces were detected by binding inhibition ELISA and SDS-PAGE; Western blot methods. The results showed that: (1) The positive rates in gastric cancer are all over 90%, when detected by cock-tail monoclonal antibodies of any three. The false positive rates are 8%- 14%. (2) Detection of cancer-associated antigens in gastric juice and feces gives higher positive rates than in serum, it shows the carbohydrate antigens is relatively more stable than the protein when it passes through the gastrointestinal canal. (3) The monoclonal antibodies against S-Tn, Tn, and glycosphingolipid antigens are good markers for the diagnosis of gastric cancer.
Antibodies, Monoclonal Antigens, Tumor-Associated, Carbohydrate