Expression of gamma-Glutamyltranspeptidase Activity in Human Oral Squamous Cancers

The enzyme activity of γ-glutamyltranspeptidase(GGT) was determined in tissues from human oral cancers and normal controls. Biochemical assay revealed that differentiated cancers had higher GGT activity compared with poorly differentiated cancers. The analysis of GGT histochemical activity was the same as that of the biochemical assay, however, the distribution pattern of GGT staining was heterogeneous. Although not all of the differentiated cancers had GGT histochemical activity, frequently GGT activity was detected only in highly keratinized horn pearls of individually keratinized cells, but not in proliferative cells. The significance of GGT expression in squamous cancers is discussed