A tumor-associated antigen in gastric cancer secretions.

An antigen, distinct from Gold's carcinoembryonic antigen, was identified in 91% of gastric cancer secretions (GCJ). Re acted with rabbit immune serum against GCJ, this antigen ap pears as one precipitin line among others on double diffusion in agargel.Whentheimmune serumhasbeenabsorbed with noncancer secretions, it gives a distinctly prevalent line with GCJ both on immunodiffusion and by immunoelectrophoresis. After absorption with normal human plasma, the gastric cancer antigen appears on immunoelectrophoresis as a sharp single line in the @3 region with a mobility greater than Gold's carcinoembryonic antigen. Gastric cancer antigen has an immunologically reactive carbohydrate moiety and is different from blood group substances. It was not detected in the gastric tumor itself. The corresponding precipitin line disappeared when the immune serum was absorbed with GCJ, thus establishing its pathognomonic significance. Detection of gastric cancer antigen may be crucial for early diagnosis, particularly in younger, still salvageable patients, when there is free HC1 on gastric analysis. INTRODUCTION The 1st immunochemical analysis of gastric secretions, carried out by Fasel and Scheidegger (5) in 1960, did not include patients with gastric cancer. Subsequent studies (1, 2, 9†" 13, 18†" 20, 24, 26, 27) completed the inventory and identification of macromolecular components in normal gastric secretion. In those including gastric cancer (1 1, 20), either an immune serum against normal gastric secretions was used or the immune serum produced against GCJ2 was not absorbed. Two reports, one by Bauer et aL (3) and the other by Karitsky and Burtin (14), deal with an autoantigen common to normal and cancerous gastric secretions. The present study is concerned with the search for an antigenic component characteristic of gastric cancer. We have used RAS's to GCJ, produced in cooperation with Dr. S. Hakomori. Specificity was increased by absorption with noncancer juices and with normal plasma. Gastric Secretion Source. One hundred four specimens of gastric secretion were collected at the Carney Hospital, Boston, Mass. Twenty-four were from documented cases of gastric cancer, 22 were from gastric ulcer, 25 were from duodenal ulcer, 16 were from gastritis, 5 were from pernicious anemia, and 12 were from normal subjects or from histologically minimal gastritis. Each pathological case was checked by X-rays, endoscopic examinations, and biopsy of the gastric mucosa or laparotomy. Histological criteria for gastritis were those of Deutsch and Christian (4). Collection. After placing a nasogastric tube and discarding the fasting specimen, we injected 50 mg Histalog …