Demonstration of gamma-glutamyl transferase, alkaline phosphatase, CEA and HCG in human lung cancer.

In contrast to its absence in normal and hyperplastic bronchial mucosa, gamma glutamyl transferase (GGT) has been demonstrated on the luminal surface of adenocarcinoma cells of bronchogenic cancer in three cases studied. On the other hand, little or no GGT was demonstrable in four epidermoid carcinomas and one oat cell cancer. Metaplastic alveolar cells appearing as cuboidal epithelial cells were uniformly positive for GGT and L-homoarginine-sensitive alkaline phosphatase. Whereas interest in GGT has centered in the past on experimental hepatocarcinogenesis, the current results demonstrate an ectopic expression of GGT in metaplastic alveolar cells and in adenocarcinoma of the lung. These findings merit further exploration to document the extent of the expression of GGT in bronchogenic cancer and to attempt to explain its presence in alveolar cell metaplasia.