| Abstract: | The effects of twice weekly topical applications of hydrogen peroxide on the buccal epithelium of Syrian hamsters were studied. Animals were treated either with hydrogen peroxide alone, with hydrogen peroxide and the carcinogen 9, 10-dimethyl-1,2-benzanthracene (DMBA), or with DMBA alone. In animals treated with 30% H2O2 alone, histopathologic examination after 22 weeks revealed hyperkeratosis and hyperplasia in all animals with hyperchromatic cells and mild dysplasia in four of nine: no tumors were seen. In animals treated with DMBA alone, three of seven (43%) developed epidermoid carcinoma, while six of 11 (55%) of animals treated with DMBA plus 3% hydrogen peroxide and five of five (100%) of animals treated with DMBA plus 30% hydrogen peroxide (P = 0.054) developed carcinoma. Thus, hydrogen peroxide can, by itself, induce pathologic changes frequently associated with preneoplastic lesions; it may also augment carcinogenesis associated with DMBA. |
