NF1 and neoplasm: Leveraging Nf1 genetically engineered mouse (GEM) models of plexiform neurofibromas [38], mast cells and T cells drive tumor formation and growth through the production of Kit ligand [61] and cytokines, like Cxcl10 [23], respectively, as well as through sustained expression of the periostin (Postn) injury response gene and increased NFkB signaling [22, 33].