Skin tumor promotion is associated with increased type V collagen content in the dermis

Tumor promotion in mouse skin depends upon establishment of hyperproliferation as well as inflammation and involves disturbance of normal communication between dermis and epidermis. As the collagenous matrix of the dermis is known to play an important role in the maintenance of normal dermal-epidermal interactions, alterations of the dermal collagen types during tumor promotion with 12-O-tetradecanoyl-phorbol-13-acetate (TPA) were investigated. In TPA-treated samples no difference between the relative content of type I and III collagen was observed, whereas the content of type V was significantly increased. When TPA treatment was discontinued before tumor development no increase of type V collagen was observed. Furthermore, treatment with the non-promoting mitogens 4-O-methyl-TPA and Ca-ionophore A 23187 did not result in any alterations of the matrix composition. These data indicate that the increase of type V collagen content is part of the disturbed tissue interactions between dermis and epidermis that facilitate tumor development.