BIOCHEMICAL AND HISTOCHEMICAL STUDIES ON VARIANT γ-GLUTAMYL TRANSPEPTIDASE (GGT) IN HUMAN GASTRIC CANCER

Abstract

In order to study γ-glutamyl transpeptidase (GGT) in gastric cancer and to detect gastric cancer specific GGT, GGT enzyme (membrane-bound) was purified from gastric cancer and kidney, immunohistochemical and immunological searches were undertaken.
GGT purified from gastric cancer as well as GGT in cytosol of gastric cancer were immunologically identical with kidney GGT in the active inhibition and in the double diffusion test using antibody against gastric cancer GGT.
However, gastric cancer GGT differed from kidney GGT in sialic acid content and sugar chains using isoelectric focusing and Con-A affinity column chromatgraphy.
On the other hand, the increase of GGT localization was observed in some histological types of gastric cancer by enzyme staining and immuno-staining. According to the histological analysis, the increase of GGT localization in gastric cancer cells resulted from one of phenotypes in relation to various gene expression.
It is considered that GGT was a useful enzyme to study enzyme transformation in tumorgenicity and that the structual change of surger chains may have possibility as a tumor marker.