Vitamin C enhances the development of carcinomas in the hamster buccal pouch experimental model

Forty young adult male Syrian hamsters (Mesocricetus auratus) were divided into four groups of 10 animals. The animals in group 1 (tumor control) had the right buccal pouches painted three times a week with a 0.5% solution of 7,12 dimethylbenz(a)anthracene in heavy mineral oil USP with the use of a number 4 sable brush. The animals in group 2 (experimental group) had the right buccal pouches painted with the same solution as group 1. In addition, they received 1 mg ascorbic acid in 0.5 ml mineral oil three times a week on days alternating with the other application. The ascorbic acid was administered by mouth with the use of a pipette. The animals in group 3 received 1 mg ascorbic acid in 0.5 ml mineral oil three times weekly, and the animals in group 4 were untreated controls. The animals were killed after 14 weeks. Tumors were counted and measured. Both right and left (control) pouches were photographed, excised, fixed in formalin, sectioned in paraffin, and studied histologically. The animals that received the ascorbic acid (vitamin C) had significantly larger tumors in the right buccal pouch, although actual numbers of gross tumors were only slightly increased. The figures for tumor burden in the animals in groups 1 and 2 were 364 versus 648 mm3. Histologic study revealed that the animals in group 2 had more anaplastic tumors and a significantly greater number of areas of dysplastic leukoplakia than the animals in group 1.