The Surface Transplantation Model to Study the Tumor–Host Interface

The tumor is a complex system comprising neoplastic genetically altered cells and a tumor stroma composed of remodeled extracellular matrix, newly formed vessels, and infiltrating host cells. The development of a cancer is a progressive multistep process in which neoplastic cells progress to malignancy by activating their microenvironment and by responding to the tumor-supporting cues of the surrounding tissue. Because of the recently recognized importance of a permissive stroma for tumor development and invasion, the host compartment is now viewed as an interesting new target for tumor therapy. Among positive regulators contributing to the elaboration of this permissive stroma are growth factors, cytokines/chemokines, proteases, and their inhibitors. The present review summarizes what we learned during the last decade on the contribution of these factors at the tumor–host interface by exploiting a useful in vivo surface transplantation model of skin carcinomas.