scholarly journals Neurofibromatosis Type 1 and tumorigenesis: molecular mechanisms and therapeutic implications

2010 ◽  
Vol 28 (1) ◽  
pp. E8 ◽  
Author(s):  
Oren N. Gottfried ◽  
David H. Viskochil ◽  
William T. Couldwell

Neurofibromatosis Type 1 (NF1) is a common autosomal dominant disease characterized by complex and multicellular neurofibroma tumors, and less frequently by malignant peripheral nerve sheath tumors (MPNSTs) and optic nerve gliomas. Significant advances have been made in elucidating the cellular, genetic, and molecular biology involved in tumor formation in NF1. Neurofibromatosis Type 1 is caused by germline mutations of the NF1 tumor suppressor gene, which generally result in decreased intracellular neurofibromin protein levels, leading to increased cascade Ras signaling to its downstream effectors. Multiple key pathways are involved with the development of tumors in NF1, including Ras/mitogen-activated protein kinase (MAPK) and Akt/mammalian target of rapamycin (mTOR). Interestingly, recent studies demonstrate that multiple other developmental syndromes (in addition to NF1) share phenotypic features resulting from germline mutations in genes responsible for components of the Ras/MAPK pathway. In general, a somatic loss of the second NF1 allele, also referred to as loss of heterozygosity, in the progenitor cell, either the Schwann cell or its precursor, combined with haploinsufficiency in multiple supporting cells is required for tumor formation. Importantly, a complex series of interactions with these other cell types in neurofibroma tumorigenesis is mediated by abnormal expression of growth factors and their receptors and modification of gene expression, a key example of which is the process of recruitment and involvement of the NF1+/– heterozygous mast cell. In general, for malignant transformation to occur, there must be accumulation of additional mutations of multiple genes including INK4A/ARF and P53, with resulting abnormalities of their respective signal cascades. Further, abnormalities of the NF1 gene and molecular cascade described above have been implicated in the tumorigenesis of NF1 and some sporadically occurring gliomas, and thus, these treatment options may have wider applicability. Finally, increased knowledge of molecular and cellular mechanisms involved with NF1 tumorigenesis has led to multiple preclinical and clinical studies of targeted therapy, including the mTOR inhibitor rapamycin, which is demonstrating promising preclinical results for treatment of MPNSTs and gliomas.

2017 ◽  
Vol 75 (6) ◽  
pp. 366-371 ◽  
Author(s):  
Roberto André Torres de Vasconcelos ◽  
Pedro Guimarães Coscarelli ◽  
Regina Papais Alvarenga ◽  
Marcus André Acioly

ABSTRACT Objective In this study, we review the institution’s experience in treating malignant peripheral nerve sheath tumors (MPNSTs). A secondary aim was to compare outcomes between MPNSTs with and without neurofibromatosis type 1 (NF1). Methods Ninety-two patients with MPNSTs, over a period of 20 years, were reviewed. A retrospective chart review was performed. The median age was 43.5 years (range, 3–84 years) and 55.4% were female; 41 patients (44.6%) had NF1-associated tumors. Results Mean tumor sizes were 15.8 ± 8.2 cm and 10.8 ± 6.3 cm for patients with and without NF1, respectively. Combined two- and five-year overall survival was 48.5% and 29%. Multivariate analysis confirmed the association of tumor size greater than 10 cm (hazard ratio (HR) 2.99; 95% confidence interval (CI) 1.14–7.85; p = 0.0258) and presence of NF1 (HR 3.41; 95%CI 1.88–6.19; p < 0.001) with a decreased overall survival. Conclusion Tumor size and NF1 status were the most important predictors of overall survival in our population.


2018 ◽  
Vol 178 (2) ◽  
pp. K1-K9 ◽  
Author(s):  
Laura Gieldon ◽  
Jimmy Rusdian Masjkur ◽  
Susan Richter ◽  
Roland Därr ◽  
Marcos Lahera ◽  
...  

Objective Our objective was to improve molecular diagnostics in patients with hereditary pheochromocytoma and paraganglioma (PPGL) by using next-generation sequencing (NGS) multi-gene panel analysis. Derived from this study, we here present three cases that were diagnosed with NF1 germline mutations but did not have a prior clinical diagnosis of neurofibromatosis type 1 (NF1). Design We performed genetic analysis of known tumor predisposition genes, including NF1, using a multi-gene NGS enrichment-based panel applied to a total of 1029 PPGL patients. We did not exclude genes known to cause clinically defined syndromes such as NF1 based on missing phenotypic expression as is commonly practiced. Methods Genetic analysis was performed using NGS (TruSight Cancer Panel/customized panel by Illumina) for analyzing patients’ blood and tumor samples. Validation was carried out by Sanger sequencing. Results Within our cohort, three patients, who were identified to carry pathogenic NF1 germline mutations, attracted attention, since none of the patients had a clinical suspicion of NF1 and one of them was initially suspected to have MEN2A syndrome due to co-occurrence of a medullary thyroid carcinoma. In these cases, one splice site, one stop and one frameshift mutation in NF1 were identified. Conclusions Since phenotypical presentation of NF1 is highly variable, we suggest analysis of the NF1 gene also in PPGL patients who do not meet diagnostic NF1 criteria. Co-occurrence of medullary thyroid carcinoma and PPGL was found to be a clinical decoy in NF1 diagnostics. These observations underline the value of multi-gene panel NGS for PPGL patients.


Genes ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 477 ◽  
Author(s):  
Kyle B. Williams ◽  
David A. Largaespada

Neurofibromatosis Type 1 (NF1) is a common genetic disorder and cancer predisposition syndrome (1:3000 births) caused by mutations in the tumor suppressor gene NF1. NF1 encodes neurofibromin, a negative regulator of the Ras signaling pathway. Individuals with NF1 often develop benign tumors of the peripheral nervous system (neurofibromas), originating from the Schwann cell linage, some of which progress further to malignant peripheral nerve sheath tumors (MPNSTs). Treatment options for neurofibromas and MPNSTs are extremely limited, relying largely on surgical resection and cytotoxic chemotherapy. Identification of novel therapeutic targets in both benign neurofibromas and MPNSTs is critical for improved patient outcomes and quality of life. Recent clinical trials conducted in patients with NF1 for the treatment of symptomatic plexiform neurofibromas using inhibitors of the mitogen-activated protein kinase (MEK) have shown very promising results. However, MEK inhibitors do not work in all patients and have significant side effects. In addition, preliminary evidence suggests single agent use of MEK inhibitors for MPNST treatment will fail. Here, we describe the preclinical efforts that led to the identification of MEK inhibitors as promising therapeutics for the treatment of NF1-related neoplasia and possible reasons they lack single agent efficacy in the treatment of MPNSTs. In addition, we describe work to find targets other than MEK for treatment of MPNST. These have come from studies of RAS biochemistry, in vitro drug screening, forward genetic screens for Schwann cell tumors, and synthetic lethal screens in cells with oncogenic RAS gene mutations. Lastly, we discuss new approaches to exploit drug screening and synthetic lethality with NF1 loss of function mutations in human Schwann cells using CRISPR/Cas9 technology.


1995 ◽  
Vol 32 (9) ◽  
pp. 706-710 ◽  
Author(s):  
M Upadhyaya ◽  
J Maynard ◽  
M Osborn ◽  
S M Huson ◽  
M Ponder ◽  
...  

2006 ◽  
Vol 20 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Judith A. Murovic ◽  
Daniel H. Kim ◽  
David G. Kline

In this paper the authors describe a patient with neurofibromatosis Type 1 (NF1) who presented with sequelae of this disease. They also review the current literature on NF1 and NF2 published between 2001 and 2005. The method used to obtain information for the case report consisted of a family member interview and a review of the patient's chart. For the literature review the authors used the search engine Ovid Medline to identify papers published on the topic between 2001 and 2005. Neurofibromatosis Type 1 appears in approximately one in 2500 to 4000 births, is caused by a defect on 17q11.2, and results in neurofibromin inactivation. The authors reviewed the current literature with regard to the following aspects of this disease: 1) diagnostic criteria for NF1; 2) criteria for other NF1-associated manifestations; 3) malignant peripheral nerve sheath tumors (PNSTs); 4) the examination protocol for a patient with an NF1-related NST; 5) imaging findings in patients with NF1; 6) other diagnostic studies; 7) surgical and adjuvant treatment for NSTs and malignant PNSTs; and 8) hormone receptors in NF1-related tumors. Pertinent illustrations are included. Neurofibromatosis Type 2 occurs much less frequently than NF1, that is, in one in 33,000 births. Mutations in NF2 occur on 22q12 and result in inactivation of the tumor suppressor merlin. The following data on this disease are presented: 1) diagnostic criteria for NF2; 2) criteria for other NF2 manifestations; 3) malignant PNSTs in patients with NF2; 4) examination protocol for the patient with NF2 who has an NST; and 5) imaging findings in patients with NF2. Relevant illustrations are included. It is important that neurosurgeons be aware of the sequelae of NF1 and NF2, because they may be called on to treat these conditions.


2020 ◽  
Vol 133 (5) ◽  
pp. 1516-1526 ◽  
Author(s):  
Charlie N. Nelson ◽  
Eva Dombi ◽  
Jared S. Rosenblum ◽  
Markku M. Miettinen ◽  
Tanya J. Lehky ◽  
...  

OBJECTIVEPatients with neurofibromatosis type 1 (NF1) are predisposed to visceral neurofibromas, some of which can progress to premalignant atypical neurofibromas (ANFs) and malignant peripheral nerve sheath tumors (MPNSTs). Though subtotal resection of ANF may prevent malignant transformation and thus deaths with no neural complications, local recurrences require reoperation. The aim of this study was to assess the surgical morbidity associated with marginal resection of targeted ANF nodules identified via preoperative serial volumetric MRI and 18F-FDG-PET imaging.METHODSThe authors analyzed clinical outcomes of 16 NF resections of 21 tumors in 11 NF1 patients treated at the NIH Clinical Center between 2008 and 2018. Preoperative volumetric growth rates and 18F-FDG-PET SUVMax (maximum standardized uptake value within the tumor) of the target lesions and any electromyographic or nerve conduction velocity abnormalities of the parent nerves were measured and assessed in tandem with postoperative complications, histopathological classification of the resected tumors, and surgical margins through Dunnett’s multiple comparisons test and t-test. The surgical approach for safe marginal resection of ANF was also described.RESULTSEleven consecutive NF1 patients (4 male, 7 female; median age 18.5 years) underwent 16 surgical procedures for marginal resections of 21 tumors. Preoperatively, 13 of the 14 (93%) sets of serial MRI studies and 10 of the 11 (91%) 18F-FDG-PET scans showed rapid growth (≥ 20% increase in volume per year) and avidity (SUVMax ≥ 3.5) of the identified tumor, respectively (median tumor size 48.7 cm3; median growth rate 92% per year; median SUVMax 6.45). Most surgeries (n = 14, 88%) resulted in no persistent postoperative parent nerve–related complications, and to date, none of the resected tumors have recurred. The median length of postoperative follow-up has been 2.45 years (range 0.00–10.39 years). Histopathological analysis confirmed significantly greater SUVMax among the ANFs (6.51 ± 0.83, p = 0.0042) and low-grade MPNSTs (13.8, p = 0.0001) than in benign neurofibromas (1.9).CONCLUSIONSThis report evaluates the utility of serial imaging (MRI and 18F-FDG-PET SUVMax) to successfully detect ANF and demonstrates that safe, fascicle-sparing gross-total, extracapsular resection of ANF is possible with the use of intraoperative nerve stimulation and microdissection of nerve fascicles.


Sign in / Sign up

Export Citation Format

Share Document