Attempts to Produce Cancer in Epidermis by Isolation in vivo

These observations show that epidermis separated from its associated connective tissue and implanted in ectopic locations in vivo can survive for as long as 9 months and does not develop neoplastic tendencies. We, therefore, consider it unlikely that the regular organisation of the skin is the product of a balance between persistent invasive tendencies displayed by epidermis and restraint exercised by the dermis, or that carcinogenesis is the result of failure of such a dermal function. The results indicate that epidermal neoplasia is not the outcome of mere removal or failure of dermal control, but more likely of abnormal influences exerted by the dermis and/or derangements in the epidermis itself. It is also concluded that epidermis, like bladder epithelium, is a weak inducer of bone formation.