Gamma-glutamyl transpeptidase in precancerous lesions and carcinomas of oral, pharyngeal, and laryngeal mucosa.

This study was undertaken to determine whether gamma-glutamyl transpeptidase (GGT) histochemical activity is expressed during the development of human oral, pharyngeal, and laryngeal squamous neoplasms. Surgical specimens from 46 patients were sampled and unfixed frozen sections were prepared and processed for histopathologic evaluation and histochemical localization of GGT. The patients' tobacco exposure, alcohol intake, and previously diagnosed neoplastic disease were documented. Generalized or patchy GGT histochemical activity was observed in each of 22 squamous cell carcinomas and in each of 33 dysplastic samples. Thus, GGT appears to be expressed during the development of malignant squamous epithelial neoplasms of the oral-pharyngeal-laryngeal region. In addition, the detection of GGT activity in several samples of nondysplastic epithelium, obtained from patients at high risk of developing cancer in this region, raises the possibility that this marker is expressed in very early precancerous sites that have not yet developed the histologic hallmarks of premalignancy.