Regression by vitamin E of experimental oral cancer.

Vitamin E was shown to regress established epidermoid carcinomas of Syrian hamster buccal pouch in 20 experimental animals following tumor induction by applications three times a week of 0.5% 7,12-dimethylbenz[a]anthracene (CAS: 57-97-6) in mineral oil for 13 weeks. The vitamin E was injected into the tumor-bearing buccal pouch twice weekly for 4 weeks in a dose of 250 micrograms in minimum essential medium. Twenty animals were maintained as untreated controls, and another 20 animals were sham-inoculated vehicle controls. Microscopic examination of buccal pouches with regressed tumor showed small epidermoid carcinomas with degeneration of tumor cells and a dense infiltrate of leukocytes, lymphocytes, and histiocytes. Buccal pouches of control animals showed large well-differentiated or moderately differentiated epidermoid carcinomas. The hamster buccal pouch cancer model presents many similarities to human oral cancer, including expression of the same oncogene, and these results offer hope for the chemotherapy of human oral cancer with the use of a relatively nontoxic agent injected locally.