A quantitative cytochemical study of three oxidative enzymes during experimental oral carcinogenesis in the hamster

The activities of three oxidative enzymes have been assayed by quantitative cytochemical methods during chemically induced carcinogenesis in the hamster cheek pouch. Changes in the levels of succinate and glucose-6-phosphate dehydrogenases were apparent in the early stages of carcinogenesis prior to the development of lesions recognisable histologically as squamous cell carcinomas. In contrast the activity of lactate dehydrogenase remained constant until malignant lesions were well established. These changes were not observed in benign hyperplastic lesions, suggesting that such enzyme assays may be of value in the diagnosis of premalignant lesions of the oral mucosa.