IHC and WB showed the expression of CPI-17 is upregulated in the sporadic VS. NF2 mutation and CPI-17 are positively correlated with merlin phosphorylation.
We hypothesize that genomic variants including deletions, insertions, inversions, and tandem duplications beyond the changes in tumor suppressor NF2 gene affect gene expression of tumor-specific pathways in vestibular schwannomas (VS) patients with Neurofibromatosis type 2 (NF2), thus contributing to their clinical behavior.
Previous research has shown that although NF2 gene mutation is the major cause of vestibular schwannoma (VS), it may not directly participate in cystic VS (CVS).
Immunohistochemical staining showed that increased nuclear YAP expression in VSs was positively correlated with high Ki-67 index and low Merlin expression.
We suggest that a lack of NF2 protein in VS and a lack of TSC1/TSC2 proteins in SGCT significantly influence this fundamental difference between the two tumor types by changing the dominant TAM type.
We suggest that lack of NF2 protein in VS and lack of TSC1/2 proteins in SGCT determine this fundamental difference between the two tumor types, by defining the predominant TAM type.
All VS and many meningiomas result from loss of the neurofibromatosis type 2 (NF2) gene product merlin, with ensuing PAK hyperactivation and increased cell proliferation/survival.
The present three children had (1) small (<1 cm), bilateral vestibular schwannomas (VSs) detected (as an incidental finding) at magnetic resonance imaging (MRI) by the age of 4 to 5 months that were asymptomatic for 10 to 14 years, with sudden and rapid (<12 months) progression in two cases at the age of 11 and 15 years, respectively; (2) development of large numbers of skin NF2 plaques mainly in atypical locations (i.e. face, hands, legs and knees), which reverted to normal skin appearance at the time of VSs progression; (3) lens opacities (n = 1) and NF2 retinal changes (n = 2) detected as early as age of 3-4 months; (4) diffuse (asymptomatic) high signal lesions at brain MRI in the periventricular regions (alike cortical dysplasia); and (5) unaffected first-degree relatives who did not harbour NF2 gene abnormalities.
Importantly, high level amplifications have been observed on 16p and 16q as well as on 9q, suggesting the possible involvement of several oncogenes in the tumorigenesis of VS. Our data suggest the involvement of various oncogenes and tumor suppressor genes might play a role in the genesis of the vestibular schwannomas apart from the inactivation of the NF2 gene.
We have performed DNA sequence and dosage analysis of the NF2 gene in a panel of 239 schwannoma tumours: 97 neurofibromatosis type 2 (NF2)-related schwannomas, 104 sporadic vestibular schwannomas (VS) and 38 schwannomatosis-related schwannomas.
The clinical characteristics of vestibular schwannomas and neurofibromatosis type 2 (NF2) syndromes have both been related to alterations in the NF2 gene.
Genetic analysis of vestibular schwannoma tissue revealed loss of the ring chromosome 22 and a somatic second hit in the NF2 gene on the remaining chromosome 22.