EXPRESSION OF CYTOCHROME P450S AND GLUTATHIONE S-TRANSFERASES IN HUMAN ESOPHAGUS WITH SQUAMOUS-CELL CARCINOMAS

In order to clarify the expression of cytochrome P450 and glutathione S-transferase in human esophagus, 41 samples of human esophagus with s quamous-cell carcinoma were investigated by immunoblot analysis and en zyme assays, Cytochrome P450 1A2/1 was clearly expressed in microsomes , and the amount in samples with tumorous tissue was significantly gre ater than that in samples without tumorous tissues or in liver; cytoch rome P450 2B6 and 3A4/3 were expressed polymorphically. Aryl hydrocarb on hydroxylase activity was detected in microsomes and was greater in samples from smokers than non-smokers, Patients who both smoked and dr ank alcohol, however, had activity similar to that of patients without these habits, Glutathione S-transferase M1 and A1/2 protein existed p olymorphically in cytosol, and glutathione S-transferase P1-1 was dete cted in all samples,The frequency of expression of the glutathione S-t ransferase A1/2 protein was greater in patients with M1 protein than i n those without; no difference in the expression was seen for glutathi one S-transferase P1-1, Neither smoking nor drinking influenced the ex pression or activity of glutathione S-transferase. Our data support th e idea that some carcinogens can be directly activated or inactivated in human esophageal epithelium.