Cobalamin-binding protein in gastric juice as a new tumor marker in gastric cancer.

Cobalamin-binding protein (binder) in gastric juice was studied as a biochemical marker of gastric cancer. Fasting gastric juice of cancer patients and controls with benign disease was used for separation of cobalamin binders by gel filtration and DEAE-cellulose column chromatography. Physicochemical properties of the binder in gastric cancer patients were shown to have a larger molecular size and more acidic isoelectric point than the control binder. The binder was found in the gastric juice of all patients with early gastric cancer. Detection of the binder may be clinically valuable as a possible marker in the diagnosis of gastric cancer.