Homozygous Inactivation of theNF1Gene in Bone Marrow Cells from Children with Neurofibromatosis Type 1 and Malignant Myeloid Disorders

Abstract
The risk of malignant myeloid disorders in young children with neurofibromatosis type 1 is 200 to 500 times the normal risk. The gene for neurofibromatosis type 1 (NF1) encodes neurofibromin, a protein that negatively regulates signals transduced by Ras proteins. Genetic and biochemical data support the hypothesis that NF1 functions as a tumor-suppressor gene in immature myeloid cells, but inactivation of both NF1 alleles has not been demonstrated in leukemic cells from patients with neurofibromatosis type 1.