STUDIES ON CEA-LIKE SUBSTANCE IN GASTRIC JUICE

I. Studies on the determination of CEA in basal gastric juice and the clinical significance

Abstract

The CEA levels in basal gastric juice were determined by CEA RIA kit (Dainabot). The levels in groups with atrophic gastritis and gastric carcinoma of its early and advanced stages were significantly higher compared with those in normal control group (p <0.01) .
Since the upper limit of normal CEA level in basal gastric juice was estimated up to 3.0 ng/ml, CEA positivities for evaluation of diagnosis of gastric carcinoma on its early and advanced cases were 80 and 70%, respectively. However, false positive cases in peptic ulcer and atrophic gastritis were found 20% and 86%, respectively.
The CEA levels showed a good correlation with the presence of atrophic gastritis accompanied with intestinal metaplasia and the acidity of the basal gastric juice. Therefore, CEA levels were found to be significantly lowered in acidic condition of gastric juice after tetragastrin stimulation compared with the higher prestimulation values, and the CEA activity determined by RIA was markedly decreased when standard CEA was incubated in gastric juice of pH 1.9 at 37°. These facts revealed that CEA or CEA-like substance was easy to break in acidic gastric juice, presumably digested by pepsin.
In addition, since NCA was often detected in 5% saline solution of the lyophilized gastric juice by Ouchterlony's method, it was suspected that determination of CEA RIA system should be affected by the increase of NCA in gastric juice.