Possible role of connective tissue in epidermal neoplasia.

Interactions between epidermal cells have been defined within a proposed mathematical model of mammalian skin. Testing the model in a computer suggests that in highly proliferating conditions of the epidermis competition for cell space in the basal layer may be sufficient to generate considerable forces in the papillary dermis. Data shown from human and pig epidermal hyperplasia indicate that basal cells are submitted to considerable lateral forces and that these and not dermal hyperplasia are the forces responsible for the increasingly folded dermo-epidermal junction. When the model was examined in condition of persistently high mitotic rate it was found that it could remain stable only if new connective tissue synthesis was not induced by the developing papillary tension. This complex and counterproductive relationship that may occur between epidermis and dermis and its possible role in the development of neoplasia are discussed.