Studies on Trace Elements in Progressive Pathology of DMBA-Induced Hamster Buccal Pouch Carcinogenesis.

Abstract

Alterations in the levels of copper, zinc, and cadmium were investigated in both serum and buccal mucosa of hamsters in progressive pathology, namely, hyperplasia, papilloma, early invasive carcinoma, and well-differentiated squamous cell carcinoma. Hamster buccal pouch carcinogenesis was induced by tri-weekly topical application of a 0.5% solution of 7, 12-dimethylbenz(a)anthracene (DMBA) in liquid paraffin applied with a brush on the right buccal mucosa for 16 weeks. Serum copper levels and the copper/zinc ratio were generally elevated, and serum zinc levels were generally depressed, during carcinogenesis; and these alterations were related to the advancing stages of carcinogenesis. In transformed buccal mucosa, a significant decrease in the level of copper and a significant increase in the level of zinc were seen with papillomatous tissues onwards, and the alterations were progressive with the development of carcinomas. The changes in the levels of cadmium were moderate and occurred only in carcinomas. These data suggest that the alterations in the levels of copper, zinc, and copper/zinc ratio may be used as markers for pathological changes in the malignant transformation of oral mucosa.