The neurofibromas found in NF1 patients contain not only Schwann cells, but also fibroblasts, mast cells and axons. We are currently testing each cell types’ role in neurofibroma development. For example, one project is aimed at defining the role of mast cells in a mouse transgenic model of neurofibroma formation developed in our laboratory. We are also utilizing NF1 mouse models to determine what role incomplete Schwann cell differentiation plays in NF1-associated tumor development. Another project is examining the role of neurofibroma stem and progenitor cells.