gamma-Glutamyl transpeptidase localization in esophageal exfoliative cytology of a chinese population at risk for carcinoma.

gamma-Glutamyl transpeptidase (gamma-GT) localization in exfoliative esophageal specimens was evaluated in a population of 911 individuals aged 35 or older who lived in an area of China with a high incidence of esophageal squamous carcinoma. Of the total population, 24.4% was positive for gamma-GT. Graded histopathologic cellular classification revealed the following incidences: normal, 10.4% (43 of 413); hyperplasia, 22.0% (44 of 200); Grade I dysplasia, 42.4% (98 of 231); Grade II dysplasia, 46.0% (23 of 50); near-carcinoma, 100% (4 of 4); and squamous carcinoma, 77.0% (10 of 13). In these groups gamma-GT-positive cells were usually from normal esophageal squamous epithelium. A lower incidence of gamma-GT-positive cells was found for dysplastic cells (dysplasia grade I, 6.5% (15 of 231); grade II, 10.0% (5 of 50). The presence of gamma-GT-positive cells in normal esophageal squamous epithelium may prove useful for identification of suspect populations; the presence in dysplastic cells may serve as a diagnostic marker for patients who will soon progress to the carcinoma stage and who should receive early treatment and careful follow-up.