Assessment of the Significance of the Intramitochondrial Dense Body in Carcinogenesis

Abstract

Two to three weeks after treatment of skin with carcinogenic chemicals, dense round bodies appeared within many epidermal cell mitochondria. Ultrastructurally identical bodies were observed in the epidermis of skin treated with non-carcinogenic irritants and of healing skin wounds, but were not seen in the epithelial cells of murine mammary tumors induced by various agents. These structures were entirely different to those occasionally seen in the sebaceous cells of normal epidermis. It is concluded that the intramitochondrial dense body is not of significance in the carcinogenic process and probably represents a non-specific epithelial response to mild injury. As it is more commonly seen in the more superficial layers of a hyperplastic epidermis and in epithelia undergoing squamous metaplasia, it may have a role in keratinization under abnormal conditions