Mutations of the neurofibromatosis type 2 gene and lack of the gene product in vestibular schwannomas.
Schwannomas are common tumors of the nervous system and are frequently found in patients with neurofibromatosis (NF) 2. Although loss of heterozygosity in NF2 tumors suggests that the NF2 gene functions as a tumor suppressor gene, the NF2 gene shows amino acid sequence homology to structural proteins in one of which dominantly acting mutations have been described. We performed a mutational analysis in 30 vestibular schwannomas and examined the effect of mutations on the NF2 protein. We detected 18 mutations in 30 vestibular schwannomas of which seven contained loss or mutation of both NF2 alleles. Most mutations were predicted to result in a truncated protein. Mutational hot spots were not identified. Immunocytochemical studies using antibodies to the NF2 protein showed complete absence of staining in tumor Schwann cells, whereas staining was observed in normal vestibular nerve. These data indicate that loss of NF2 protein function is a necessary step in schwannoma pathogenesis and that the NF2 gene functions as a recessive tumor suppressor gene.
Neurogenetics Laboratory, Cedars-Sinai Medical Center, University of California, Los Angeles 90048.
J
J
Sainz
D P
DP
Huynh
K
K
Figueroa
N K
NK
Ragge
M E
ME
Baser
S M
SM
Pulst
D000595:Amino Acid Sequence; D001483:Base Sequence; D004252:DNA Mutational Analysis; D017931:DNA Primers; D005091:Exons; D016368:Frameshift Mutation; D016515:Genes, Neurofibromatosis 2; D005819:Genetic Markers; D006801:Humans; D007150:Immunohistochemistry; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009363:Neoplasm Proteins / Q000235:genetics; D016518:Neurofibromatosis 2 / Q000235:genetics* / Q000473:pathology; D025581:Neurofibromin 2; D017354:Point Mutation; D016133:Polymerase Chain Reaction; D012016:Reference Values; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D014725:Vestibular Nerve / Q000166:cytology / Q000378:metabolism
D017931:DNA Primers; D005819:Genetic Markers; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D025581:Neurofibromin 2