(CIT): Neurofibromatosis Type 1 (NF1) is a dominantly inherited disease in which mutation of the NF1tumor suppressor either appears de novo or is transmitted through the germ line. Biochemical and mouse knockout studies have demonstrated that NF1 is a negative regulator of the ras pathway by acting as rasGap. Dr. Parada has used conventional knockouts and cre/loxP based strategies to model tumor formation in these mice. He will discuss the current understanding of neurofibroma formation, a complex peripheral nerve tumor that is prevalent in NF1.