The long-term interest of the Ratner Research Laboratory is to define the interactions between glial cells and axons during nervous system development, and to learn how those interactions go awry in disease, with the goal of providing novel therapies to patients with nervous system disease. Neurofibromatosis type 1 (NF1) is an inherited autosomal dominant disorder (1:3,500 humans) that involves the formation of nerve-associated tumors and other non-tumor related problems. Neurofibromatosis type 2 (NF2) involves the development of schwannomas, benign tumors composed of Schwann cells (peripheral glial cells). Elucidating the mechanisms by which the nerve-associated tumors arise in both diseases can lead not only to the development of therapy for NF1 and NF2 patients, but also can prove useful in providing information about cancers that arise in the general population, especially given that NF1 mutations are found in about 10% of cancers in the general population.