Alpha 1-acid glycoprotein in gastric cancer juice.

Gastric juice was neutralized (nGJ) in vivo by 80 ml of a phosphate buffer containing radiolabelled vitamin B12 as dilution indicator. Unprocessed nGJ was analyzed in the double gel diffusion technique for the presence of serum proteins using monospecific antisera. Alpha1-Acid glycoprotein (AGP) was found in a high incidence (36 out of 38 subjects) in nGJ of gastric cancer patients. AGP was also observed less frequently in nGJ of patients with Billroth II resections (6/15), metaplasia (11/52), gastric ulcer (3/24), chronic atrophic gastritis (2/26) and chronic gastritis (3/63). AGP was absent in the control group (0/21), in patients with surface gastritis (0/38) and in subjects with normal acid secretion (0/45). Immunochemical studies demonstrated no identity of AGP with human "gastrointestinal tumor associated antigens." In 7 out of 17 AGP positive samples immunochemical differences between gastric and serum AGP were observed.