Frequency of the Loss of Heterozygosity of the NF2 Gene in Sporadic Spinal Schwannomas.

Abstract

Individuals with type 2 Neurofibromatosis are predisposed for the appearance of schwannomas. In the present study we analyzed the loss of heterozygosity and mutations in the NF2 gene in patients with sporadic Schwannoma without Neurofibromatosis type 2. We analyzed 39 patients with sporadic spinal schwannoma. We quantified the number of alleles by FISH and sequenced the NF2 gene. We identified 16/39 patients with point mutations and/or LOHs in the tumor samples analyzed. The LOHs were found in 7/39 patients. Two homozygous mutations were detected in 4/39 tumors, and the presence of the mutation in heterozygosis was revealed in 3/39 patients. In two tumors, we detected the loss of one allele of the NF2 gene, with no mutation. The genetic alterations observed in the NF2 gene indicated that spinal schwannomas are associated with genetic alterations also found in other schwannomas and type 2 Neurofibromatosis, which reinforces the etiological role of this gene.