Abstract
Schwannomas are benign tumors that arise sporadically or associated to the NF2 syndrome. The characteristic alteration in schwannomas is the loss of heterozygosity of 22q (up to 50%), where NF2 gene is located. Inactivating mutations of this gene have been found up to 66% of sporadic schwannomas and 33% of NF2-associated tumors. NF2 nonsense and frameshift mutations, both causing truncated proteins, are associated with more severe phenotypes. Merlin, the product of NF2 gene, belongs to the ERM family of proteins that connect the actin cytoskeleton with plasma membrane. Merlin functions as a tumor suppressor and is involved in cell-cell and cell-matrix interactions through an array of molecular pathways. Merlin over-expression can inhibit both cell proliferation and the transformation induced by oncogenes, and its down-regulation cause a lack in contact inhibition, leading to neoplastic transformation. Another oncogenic mechanism studied in schwannomas is the epigenetic hypermethylation of genic promoters. The study of epigenetic gene silencing in schwannomas has shown high frequencies of promoter hypermethylation in some well known cancer-related genes, and specifically on NF2 gene. There are many unknown aspects in the molecular biology of schwannomas. However, current knowledge and technical advances allows us to be optimistic about future perspectives.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
Almeida LO, Custodio AC, Pinto GR, Santos MJ, Almeida JR, Clara CA, Rey JA, Casartelli C (2009) Polymorphisms and DNA methylation of gene TP53 associated with extra-axial brain tumors. Genet Mol Res 8:8–18
Anderson TD, Loevner LA, Bigelow DC, Mirza N (2000) Prevalence of unsuspected acoustic neuroma found by magnetic resonance imaging. Otolaryngol Head Neck Surg 122:643–646
Antinheimo J, Sallinen SL, Sallinen P, Haapasalo H, Helin H, Horelli-Kuitunen N, Wessman M, Sainio M, Jaaskelainen J, Carpen O (2000) Genetic aberrations in sporadic and neurofibromatosis 2 (NF2)-associated schwannomas studied by comparative genomic hybridization (CGH). Acta Neurochir (Wien) 142:1099–1104
Ballestar E, Esteller M (2008) Epigenetic gene regulation in cancer. Adv Genet 61:247–267
Baser ME (2006) The distribution of constitutional and somatic mutations in the neurofibromatosis 2 gene. Hum Mutat 27:297–306
Baser ME, Makariou EV, Parry DM (2002) Predictors of vestibular schwannoma growth in patients with neurofibromatosis Type 2. J Neurosurg 96:217–222
Bello MJ, Martinez-Glez V, Franco-Hernandez C, Pefla-Granero C, de Campos JM, Isla A, Lassaletta L, Vaquero J, Rey JA (2007) DNA methylation pattern in 16 tumor-related genes in schwannomas. Cancer Genet Cytogenet 172:84–86
Bruder CE, Ichimura K, Tingby O, Hirakawa K, Komatsuzaki A, Tamura A, Yuasa Y, Collins VP, Dumanski JP (1999) A group of schwannomas with interstitial deletions on 22q located outside the NF2 locus shows no detectable mutations in the NF2 gene. Hum Genet 104:418–424
Caye-Thomasen P, Werther K, Nalla A, Bog-Hansen TC, Nielsen HJ, Stangerup SE, Thomsen J (2005) VEGF and VEGF receptor-1 concentration in vestibular schwannoma homogenates correlates to tumor growth rate. Otol Neurotol 26:98–101
Doherty JK, Ongkeko W, Crawley B, Andalibi A, Ryan AF (2008) ErbB and Nrg: potential molecular targets for vestibular schwannoma pharmacotherapy. Otol Neurotol 29:50–57
Evans DG (2009) Neurofibromatosis type 2 (NF2): a clinical and molecular review. Orphanet J Rare Dis 4:16
Flaiz C, Chernoff J, Ammoun S, Peterson JR, Hanemann CO (2009) PAK kinase regulates Rac GTPase and is a potential target in human schwannomas. Exp Neurol 218:137–144
Gonzalez-Gomez P, Bello MJ, Alonso ME, Lomas J, Arjona D, Campos JM, Vaquero J, Isla A, Lassaletta L, Gutierrez M, Sarasa JL, Rey JA (2003) CpG island methylation in sporadic and neurofibromatis type 2-associated schwannomas. Clin Cancer Res 9:5601–5606
Hanemann CO, Evans DG (2006) News on the genetics, epidemiology, medical care and translational research of Schwannomas. J Neurol 253:1533–1541
Hansen MR, Roehm PC, Chatterjee P, Green SH (2006) Constitutive neuregulin-1/ErbB signaling contributes to human vestibular schwannoma proliferation. Glia 53:593–600
Kino T, Takeshima H, Nakao M, Nishi T, Yamamoto K, Kimura T, Saito Y, Kochi M, Kuratsu J, Saya H, Ushio Y (2001) Identification of the cis-acting region in the NF2 gene promoter as a potential target for mutation and methylation-dependent silencing in schwannoma. Genes Cells 6:441–454
Kluwe L, Mautner V, Heinrich B, Dezube R, Jacoby LB, Friedrich RE, MacCollin M (2003) Molecular study of frequency of mosaicism in neurofibromatosis 2 patients with bilateral vestibular schwannomas. J Med Genet 40:109–114
Kullar PJ, Pearson DM, Malley DS, Collins VP, Ichimura K (2010) CpG island hypermethylation of the NF2 gene is rare in sporadic vestibular schwannomas. Neuropathol Appl Neurobiol 36:505–514
Lassaletta L, Bello MJ, Del Rio L, Alfonso C, Roda JM, Rey JA, Gavilan J (2006) DNA methylation of multiple genes in vestibular schwannoma: relationship with clinical and radiological findings. Otol Neurotol 27:1180–1185
MacCollin M, Chiocca EA, Evans DG, Friedman JM, Horvitz R, Jaramillo D, Lev M, Mautner VF, Niimura M, Plotkin SR, Sang CN, Stemmer-Rachamimov A, Roach ES (2005) Diagnostic criteria for schwannomatosis. Neurology 64:1838–1845
McClatchey AI, Fehon RG (2009) Merlin and the ERM proteins—regulators of receptor distribution and signaling at the cell cortex. Trends Cell Biol 19:198–206
Moller MN, Werther K, Nalla A, Stangerup SE, Thomsen J, Bog-Hansen TC, Nielsen HJ, Caye-Thomasen P (2010) Angiogenesis in vestibular schwannomas: expression of extracellular matrix factors MMP-2, MMP-9, and TIMP-1. Laryngoscope 120:657–662
Neff BA, Welling DB, Akhmametyeva E, Chang LS (2006) The molecular biology of vestibular schwannomas: dissecting the pathogenic process at the molecular level. Otol Neurotol 27:197–208
Okada M, Wang Y, Jang SW, Tang X, Neri LM, Ye K (2009) Akt phosphorylation of merlin enhances its binding to phosphatidylinositols and inhibits the tumor-suppressive activities of merlin. Cancer Res 69:4043–4051
Patronas NJ, Courcoutsakis N, Bromley CM, Katzman GL, MacCollin M, Parry DM (2001) Intramedullary and spinal canal tumors in patients with neurofibromatosis 2: MR imaging findings and correlation with genotype. Radiology 218:434–442
Rong R, Surace EI, Haipek CA, Gutmann DH, Ye K (2004) Serine 518 phosphorylation modulates merlin intramolecular association and binding to critical effectors important for NF2 growth suppression. Oncogene 23:8447–8454
Scoles DR (2008) The merlin interacting proteins reveal multiple targets for NF2 therapy. Biochim Biophys Acta 1785:32–54
Sharma S, Kelly TK, Jones PA (2010) Epigenetics in cancer. Carcinogenesis 31:27–36
Sobel RA (1993) Vestibular (acoustic) schwannomas: histologic features in neurofibromatosis 2 and in unilateral cases. J Neuropathol Exp Neurol 52:106–113
Warren C, James LA, Ramsden RT, Wallace A, Baser ME, Varley JM, Evans DG (2003) Identification of recurrent regions of chromosome loss and gain in vestibular schwannomas using comparative genomic hybridisation. J Med Genet 40:802–806
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2012 Springer Science+Business Media B.V.
About this chapter
Cite this chapter
Martínez-Glez, V., Torres-Martín, M., Castresana, J.S., Lassaletta, L., Rey, J.A. (2012). Schwannomas: Role of Molecular Genetics and Epigenetic Mechanisms. In: Hayat, M. (eds) Tumors of the Central Nervous System, Volume 7. Tumors of the Central Nervous System, vol 7. Springer, Dordrecht. https://doi.org/10.1007/978-94-007-2894-3_24
Download citation
DOI: https://doi.org/10.1007/978-94-007-2894-3_24
Published:
Publisher Name: Springer, Dordrecht
Print ISBN: 978-94-007-2893-6
Online ISBN: 978-94-007-2894-3
eBook Packages: MedicineMedicine (R0)