Creation of an international registry to support discovery in schwannomatosis.

Schwannomatosis is a tumor suppressor syndrome that causes multiple tumors along peripheral nerves. Formal diagnostic criteria were first published in 2005. Variability in clinical presentation and a relative lack of awareness of the syndrome have contributed to difficulty recognizing affected individuals and accurately describing the natural history of the disorder. Many critical questions such as the mutations underlying schwannomatosis, genotype-phenotype correlations, inheritance patterns, pathologic diagnosis of schwannomatosis-associated schwannomas, tumor burden in schwannomatosis, the incidence of malignancy, and the effectiveness of current, or new treatments remain unanswered. A well-curated registry of schwannomatosis patients is needed to facilitate research in field. An international consortium of clinicians and scientists across multiple disciplines with expertise in schwannomatosis was established and charged with the task of designing and populating a schwannomatosis patient registry. The International Schwannomatosis Registry (ISR) was built around key data points that allow confirmation of the diagnosis and identification of potential research subjects to advance research to further the knowledge base for schwannomatosis. A registry with 389 participants enrolled to date has been established. Twenty-three additional subjects are pending review. A formal process has been established for scientific investigators to propose research projects, identify eligible subjects, and seek collaborators from ISR sites. Research collaborations have been created using the information collected by the registry and are currently being conducted. The ISR is a platform from which multiple research endeavors can be launched, facilitating connections between affected individuals interested in participating in research and researchers actively investigating a variety of aspects of schwannomatosis. © 2016 Wiley Periodicals, Inc.

Growth in neurofibromatosis 1 microdeletion patients.

Microdeletions of the entire NF1 gene and surrounding genomic region occur in about 5% of patients with neurofibromatosis 1 (NF1). NF1 microdeletion patients usually have more cutaneous and plexiform neurofibromas and a higher risk of developing malignant peripheral nerve sheath tumors than other people with NF1. Somatic overgrowth has also been observed in NF1 microdeletion patients, an observation that is remarkable because most NF1 patients are smaller than average for age and sex. We studied longitudinal measurements of height, weight, and head circumference in 56 patients with NF1 microdeletions and 226 NF1 patients with other kinds of mutations. Although children with NF1 microdeletions were much taller than non-deletion NF1 patients at all ages after 2 years, the lengths of deletion and nondeletion NF1 patients were similar in early infancy. NF1 microdeletion patients tended to be heavier than other NF1 patients, but height or weight more than 3 standard deviations above the mean for age and sex was infrequent in children with NF1 microdeletions. Head circumference and age of puberty were similar in deletion and non-deletion NF1 patients. The pattern of growth differs substantially in deletion and non-deletion NF1 patients, but the pathogenic basis for this difference is unknown.

Bevacizumab treatment for symptomatic spinal ependymomas in neurofibromatosis type 2.

BACKGROUND: Neurofibromatosis type 2 (NF2) is a tumor suppressor syndrome associated with vestibular schwannomas, meningiomas, and spinal ependymomas. There have been anecdotal reports of radiographic response of spinal ependymomas in NF2 patients being treated for progressive vestibular schwannomas with bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF). AIMS: The aim of this study was to review the clinical effects of bevacizumab treatment for symptomatic, NF2-associated ependymomas METHODS: We conducted a retrospective review of all patients with NF2 treated with bevacizumab for symptomatic ependymoma at three NF2 specialty centers. Tumor size was evaluated by linear measurements; radiographic response was defined as >20% reduction in tumor size. We also performed immunohistochemical evaluation of NF2-associated symptomatic ependymomas from five patients, including two from this clinical series. RESULTS: Eight patients with NF2 and symptomatic ependymoma were treated with bevacizumab. All patients had subjective clinical improvement with bevacizumab, although only five of eight patients evaluated had radiographic response. All tumors expressed VEGF-R2. Four of five evaluated ependymomas expressed VEGF-R1; one without VEGF-R1 expression was from a patient who showed clinical but not radiographic response. CONCLUSIONS: Treatment using bevacizumab improved symptoms related to NF2-associated ependymomas, often without concurrent radiographic response. This treatment effect may be related to VEGF-R1 expression in NF2-associated ependymoma.

Cardiac characterization of 16 patients with large NF1 gene deletions.

The aim of this study was to characterize cardiac features of patients with neurofibromatosis 1 (NF1) and large deletions of the NF1 gene region. The study participants were 16 patients with large NF1 deletions and 16 age- and sex-matched NF1 patients without such deletions. All the patients were comprehensively characterized clinically and by echocardiography. Six of 16 NF1 deletion patients but none of 16 non-deletion NF1 patients have major cardiac abnormalities (p = 0.041). Congenital heart defects (CHDs) include mitral insufficiency in two patients and ventricular septal defect, aortic stenosis, and aortic insufficiency in one patient each. Three deletion patients have hypertrophic cardiomyopathy. Two patients have intracardiac tumors. NF1 patients without large deletions have increased left ventricular (LV) diastolic posterior wall thickness (p < 0.001) and increased intraventricular diastolic septal thickness (p = 0.001) compared with a healthy reference population without NF1, suggestive of eccentric LV hypertrophy. CHDs and other cardiovascular anomalies are more frequent among patients with large NF1 deletion and may cause serious clinical complications. Eccentric LV hypertrophy may occur in NF1 patients without whole gene deletions, but the clinical significance of this finding is uncertain. All patients with clinical suspicion for NF1 should be referred to a cardiologist for evaluation and surveillance.

Ipsilateral Vestibular Schwannoma after Cochlear Implantation.

OBJECTIVE: The vestibular schwannoma incidence rate is approximately 4.2 per 100,000/year. Thus far, about 700,000 cochlear implantations have been performed worldwide; therefore, the occurrence of vestibular schwannoma postcochlear implantations can be assumed to be infrequent. Recent developments allow safe observation and surveillance of the implanted-side internal auditory canal (IAC) and cochlea by magnetic resonance imaging (MRI), even after cochlear implantation. Patients. A 71-year-old woman with sudden hearing loss and a contralateral vestibular schwannoma without clinical and genetic signs of neurofibromatosis type II. Intervention(s). Ipsilateral cochlear implantation and contralateral vestibular schwannoma extirpation with regular tumor follow-up. Main Outcome Measure(s). Comparison of ipsilateral pre and postcochlear implantation 3T MRI T1 GAD. RESULTS: We observed a tumor growing at the fundus of the internal auditory canal 1 year after cochlear implantation on the ipsilateral side. Although first detected after cochlear implantation beside a known vestibular schwannoma on the contralateral side, a scan slice thickness of 2 mm cannot fully exclude the preoperative persistence of a small tumor. Based on the clinical findings and after genetic exclusion of NFII, the patient was classified as a NFII mosaic type. CONCLUSION: Even after cochlear implantation, tumors in the IAC causing vertigo, facial palsy, and affecting the audiologic outcome can be detected by MRI. The MRI slice thickness used before cochlear implantation should be under 2 mm.

Clinical characterisation of 29 neurofibromatosis type-1 patients with molecularly ascertained 1.4 Mb type-1 NF1 deletions.

BACKGROUND: Large deletions of the NF1 gene region occur in approximately 5% of patients with neurofibromatosis type-1 (NF1) and are associated with particularly severe manifestations of the disease. However, until now, the genotype-phenotype relationship has not been comprehensively studied in patients harbouring large NF1 gene deletions of comparable extent (giving rise to haploinsufficiency of the same genes). METHOD: We have performed the most comprehensive clinical/neuropsychological characterisation so far undertaken in NF1 deletion patients, involving 29 patients with precisely determined type-1 NF1 (1.4 Mb) deletions. RESULTS: Novel clinical features found to be associated with type-1 NF1 deletions included pes cavus (17% of patients), bone cysts (50%), attention deficit (73%), muscular hypotonia (45%) and speech difficulties (48%). Type-1 NF1 deletions were found to be disproportionately associated with facial dysmorphic features (90% of patients), tall stature (46%), large hands and feet (46%), scoliosis (43%), joint hyperflexibility (72%), delayed cognitive development and/or learning disabilities (93%) and mental retardation (IQ<70; 38%), as compared with the general NF1 patient population. Significantly increased frequencies (relative to the general NF1 population) of plexiform neurofibromas (76%), subcutaneous neurofibromas (76%), spinal neurofibromas (64%) and MPNSTs (21%) were also noted in the type-1 deletion patients. Further, 50% of the adult patients exhibited a very high burden of cutaneous neurofibromas (N>or=1000). CONCLUSION: These findings emphasise the importance of deletion analysis in NF1 since frequent monitoring of tumour presence and growth could potentiate early surgical intervention thereby improving patient survival.

High bone turnover and accumulation of osteoid in patients with neurofibromatosis 1.

UNLABELLED: Although it is known that neurofibromatosis 1 (NF1) patients suffer from vitamin D deficiency and display decreased bone mineral density (BMD), a systematic clinical and histomorphometrical analysis is absent. Our data demonstrate that NF1 patients display high bone turnover and accumulation of osteoid and that supplementation of vitamin D has a beneficial effect on their BMD. INTRODUCTION: Neurofibromatosis 1 results in a wide range of clinical manifestations, including decreased BMD. Although it has been reported that NF1 patients have decreased vitamin D serum levels, the manifestation of the disease at the bone tissue level has rarely been analyzed. METHODS: Thus, we performed a clinical evaluation of 14 NF1 patients in comparison to age- and sex-matched control individuals. The analysis included dual X-ray absorptiometry osteodensitometry, laboratory parameters, histomorphometric and quantitative backscattered electron imaging (qBEI) analyses of undecalcified bone biopsies. RESULTS: NF1 patients display significantly lower 25-(OH)-cholecalciferol serum levels and decreased BMD compared to control individuals. Histomorphometric analysis did not only reveal a reduced trabecular bone volume in biopsies from NF1 patients, but also a significantly increased osteoid volume and increased numbers of osteoblasts and osteoclasts. Moreover, qBEI analysis revealed a significant decrease of the calcium content in biopsies from NF1 patients. To address the question whether a normalization of calcium homeostasis improves BMD in NF1 patients, we treated four patients with cholecalciferol for 1 year, which resulted in a significant increase of BMD. CONCLUSION: Taken together, our data provide the first complete histomorphometric analysis from NF1 patients. Moreover, they suggest that low vitamin D levels significantly contribute to the skeletal defects associated with the disease.

Bone health and fracture rate in individuals with neurofibromatosis 1 (NF1).

BACKGROUND: Patients with neurofibromatosis 1 (NF1) are shorter than expected and often have low bone mineral density (BMD), but the pathogenesis of these bony problems is poorly understood. METHODS: We performed an exploratory study of BMD, 18 laboratory measures of bone metabolism, and fracture history in 72 adult NF1 patients. RESULTS: Eight of the 18 clinical biochemical measures of bone health had at least 10% of NF1 patients outside the standard reference range. Serum 25-hydroxy-vitamin D concentrations were low in 56% of the NF1 patients, serum parathyroid hormone (PTH) concentrations were high in 34%, and urine deoxypyridinoline cross-link concentrations were high in 50%. Mean serum 25-hydroxy-vitamin D concentrations were significantly lower in people with NF1 than in season matched controls in both summer (p = 0.008) and winter (p<0.001). 36 (50%) of the 72 people with NF1 studied had BMD consistent with osteopenia, and 14 (19%) had BMD consistent with osteoporosis. High serum PTH concentration, high serum bone tartrate resistant acid phosphatase concentration, and high serum calcium concentration were associated with lower BMD among the NF1 patients. Males were more likely than females to have low BMD. The reported frequency of fractures in individuals with NF1 was much higher than in their unaffected siblings and spouses (p<0.001), and pathological fractures were reported only in NF1 patients. CONCLUSION: People with NF1 often have a generalised abnormality of bone metabolism. Further studies are needed to determine the biochemical and molecular basis of this abnormality.

Longitudinal study of neurofibromatosis 1 associated plexiform neurofibromas.

BACKGROUND: Plexiform neurofibromas are benign tumours that occur in more than half of people with neurofibromatosis 1 (NF1). These tumours can cause serious complications and can also progress to malignant peripheral nerve sheath tumours (MPNSTs), one of the leading causes of death among NF1 patients. Plexiform neurofibromas are clinically heterogeneous, and knowledge of their natural history is limited. In order to characterise the growth of plexiform neurofibromas better, we performed serial magnetic resonance imaging (MRI) in NF1 patients with such tumours. METHODS: MRI was done on 44 plexiform neurofibromas in 34 NF1 patients (median age 10 years; range 1-47 years). Each tumour was measured in two dimensions from the MRI scan, and the area and growth rate were calculated. The median length of follow-up was 6 years, with an average interval of 3 years between scans. RESULTS: 36 tumours remained stable in size throughout the period of follow-up. 8 tumours increased in size; all occurred in patients who were under 21 years of age when first studied. The single exception was a man who developed rapid tumour growth and pain in a plexiform neurofibroma that had been followed for 10 years. Biopsy showed the presence of an MPNST. CONCLUSION: Longitudinal MRI is a valuable means of monitoring the growth of plexiform neurofibromas in individuals with NF1.

Surface distribution of LETS protein in relation to the cytoskeleton of normal and transformed cells.

The organization of LETS protein on the surface of NIL8 hamster cells has been examined by immunofluorescence staining. The distribution of LETS protein was found to depend on the culture conditions; in subconfluent, low-serum arrested cultures the LETS protein is predominantly located at the cell-substrate interface and also in regions of cell-cell contact, whereas in dense cultures the cells are surrounded by a network of LETS protein fibrils. Transformed derivatives of these cells exhibit only sporadic staining for LETS protein, in the form of short intercellular bridges. Agents that cause alterations in cell shape and cytoplasmic filaments have been used to explore the relationship of LETS protein to the internal cytoskeletal elements. Reciprocally, perturbations of the cell surface were examined for their effects on internal filaments. The arrangement of microtubules seems to be unrelated to the presence of LETS protein in the cells studied. Actin microfilament bundles and LETS protein respond in a coordinate fashion to some perturbants but independently with respect to others. The patterns of staining for LETS protein are consistent with an involvement in cell-to-cell and cell-to-substrate adhesion.

CAPE (caffeic acid phenethyl ester)-based propolis extract (Bio 30) suppresses the growth of human neurofibromatosis (NF) tumor xenografts in mice.

Dysfunction of the NF1 gene coding a RAS GAP is the major cause of neurofibromatosis type 1 (NF1), whereas neurofibromatosis type 2 (NF2) is caused primarily by dysfunction of the NF2 gene product called merlin that inhibits directly PAK1, an oncogenic Rac/CDC42-dependent Ser/Thr kinase. It was demonstrated previously that PAK1 is essential for the growth of both NF1 and NF2 tumors. Thus, several anti-PAK1 drugs, including FK228 and CEP-1347, are being developed for the treatment of NF tumors. However, so far no effective NF therapeutic is available on the market. Since propolis, a very safe healthcare product from bee hives, contains anticancer ingredients called CAPE (caffeic acid phenethyl ester) or ARC (artepillin C), depending on the source, both of which block the oncogenic PAK1 signaling pathways, its potential therapeutic effect on NF tumors was explored in vivo. Here it is demonstrated that Bio 30, a CAPE-rich water-miscible extract of New Zealand (NZ) propolis suppressed completely the growth of a human NF1 cancer called MPNST (malignant peripheral nerve sheath tumor) and caused an almost complete regression of human NF2 tumor (Schwannoma), both grafted in nude mice. Although CAPE alone has never been used clinically, due to its poor bioavailability/water-solubility, Bio 30 contains plenty of lipids which solubilize CAPE, and also includes several other anticancer ingredients that seem to act synergistically with CAPE. Thus, it would be worth testing clinically to see if Bio 30 and other CAPE-rich propolis are useful for the treatment of NF patients.

Germline and somatic NF1 gene mutation spectrum in NF1-associated malignant peripheral nerve sheath tumors (MPNSTs).

About 10% of neurofibromatosis type 1 (NF1) patients develop malignant peripheral nerve sheath tumors (MPNSTs) and represent considerable patient morbidity and mortality. Elucidation of the genetic mechanisms by which inherited and acquired NF1 disease gene variants lead to MPNST development is important. A study was undertaken to identify the constitutional and somatic NF1 mutations in 34 MPNSTs from 27 NF1 patients. The NF1 germline mutations identified in 22 lymphocytes DNA from these patients included seven novel mutations and a large 1.4-Mb deletion. The NF1 germline mutation spectrum was similar to that previously identified in adult NF1 patients without MPNST. Somatic NF1 mutations were identified in tumor DNA from 31 out of 34 MPNSTs, of which 28 were large genomic deletions. The high prevalence (>90%) of such deletions in MPNST contrast with the =or<20% found in benign neurofibromas and is indicative of the involvement of different mutational mechanisms in these tumors. Coinactivation of the TP53 gene by deletion, or by point mutation along with NF1 gene inactivation, is known to exacerbate disease symptoms in NF1, therefore TP53 gene inactivation was screened. DNA from 20 tumors showed evidence for loss of heterozygosity (LOH) across the TP53 region in 11 samples, with novel TP53 point mutations in four tumors.

Malignant peripheral nerve sheath tumors (MPNST) in NF1-affected children.

BACKGROUND: Malignant peripheral nerve sheath tumors (MPNST) constitute a heterogeneous group of malignant tumors that probably arise from cells of the peripheral nerve sheath. Association of MPNST with neurofibromatosis type 1 (NF1) is frequently reported. MPNST contribute significantly to the reduced life-span of NF1-patients. At present there are only sparse data on MPNST in NF1-children. The aim of this study was to determine the outcome of children affected with NF1 who developed an MPNST. MATERIALS AND METHODS: Over the period of 1985 to 2005, we followed 52 NF1 patients with MPNST at our outpatient department. All patients were diagnosed and re-evaluated according to the updated NIH diagnostic criteria for NF1. RESULTS: Out of this cohort, 8 patients with MPNST were aged 1 to 17 years at the time of MPNST diagnosis (mean age: 12 years; 5 girls and 3 boys). We noticed the following characteristics: MPNST arose from plexiform neurofibromas (PNF) with invasive or displacing growth pattern on MRI. Many patients reported pain and neurological deficits at the time of presentation. Diagnosis of MPNST in this age group took longer compared to adults. This cohort did not show longer survival periods than adults with MPNST. Adjunctive treatment with chemotherapy or radiation had no lasting effect. The overall survival time of this small cohort was 30.5 months. Those children who died showed a median survival time after diagnosis of 20 months. The longest survival of 112 months was achieved for a girl who presented with MPNST of the distal upper arm and underwent amputation. The NF1 mutation analysis in the MPNST pediatric age group revealed the same mutational spectrum as the adult group. CONCLUSION: Our data reveal MPNST in children with NF1. Children cannot verbalize physical alterations adequately; therefore the correct diagnosis might be hampered in these patients. Unresolved complaints of children with NF1 should be investigated thoroughly due to the risk for malignancy in NF1.

Clinical relevance of positron emission tomography and magnetic resonance imaging in the progression of internal plexiform neurofibroma in NF1.

Neurofibromatosis type 1 (NF1) is a frequent and inherited disease with a predisposition for malignant peripheral nerve sheath tumor (MPNST) development. MPNST are soft tissue sarcomas that arise from peripheral nerves, being one of the most aggressive malignancies in humans with extremely poor prognosis. MPNST frequently arise from a previously undetected plexiform neurofibroma (PNF). The malignant transformation of an internal PNF to an MPNST is difficult to assess and requires advanced imaging techniques like magnetic resonance imaging or positron emission tomography. Despite the high quality of current diagnostics, the changing tumor biology inside a plexiform neurofibroma cannot currently be visualized accurately. We report 4 cases of NF1 patients with PNF who showed imaging findings suspicious for malignant degeneration, but proved to have MPNST in only one case. Three tumors might represent an intermediate type between PNF and MPNST. Ablative surgery and complete histological work-up of specimens is the only way to clarify tumor status, thereby enabling provision of adequate local treatment.

Vitamin D deficiency associated with number of neurofibromas in neurofibromatosis 1.

Neurofibromatosis 1 (NF1) is a tumour suppressor gene syndrome characterized by multiple cutaneous and plexiform neurofibromas. Focal osseous abnormalities, short stature, and decreased bone mineral density are also frequent in people with NF1. We measured serum 25-hydroxyvitamin D concentrations in 55 patients with NF1 and 58 healthy controls, and correlated the findings in the patients with NF1 with their estimated number of dermal neurofibromas. Geometric mean (SD) serum 25-hydroxyvitamin D concentration was 14.0 (1.6) ng/mL among the patients with NF1 compared with 31.4 (1.7) ng/mL among healthy controls (p<<0.0001). The serum vitamin D concentration and number of dermal neurofibromas reported by patients with NF1 were inversely correlated (Spearman's rho = -0.572, p<0.00001). The occurrence of low serum vitamin D concentrations in people with NF1, especially those with many dermal neurofibromas, may provide new pathogenic insights and have important therapeutic implications.

Identification of novel deletion breakpoints bordered by segmental duplications in the NF1 locus using high resolution array-CGH.

BACKGROUND: Segmental duplications flanking the neurofibromatosis type 1 (NF1) gene locus on 17q11 mediate most gene deletions in NF1 patients. However, the large size of the gene and the complexity of the locus architecture pose difficulties in deletion analysis. We report the construction and application of the first NF1 locus specific microarray, covering 2.24 Mb of 17q11, using a non-redundant approach for array design. The average resolution of analysis for the array is approximately 12 kb per measurement point with an increased average resolution of 6.4 kb for the NF1 gene. METHODS: We performed a comprehensive array-CGH analysis of 161 NF1 derived samples and identified heterozygous deletions of various sizes in 39 cases. The typical deletion was identified in 26 cases, whereas 13 samples showed atypical deletion profiles. RESULTS: The size of the atypical deletions, contained within the segment covered by the array, ranged from 6 kb to 1.6 Mb and their breakpoints could be accurately determined. Moreover, 10 atypical deletions were observed to share a common breakpoint either on the proximal or distal end of the deletion. The deletions identified by array-CGH were independently confirmed using multiplex ligation-dependent probe amplification. Bioinformatic analysis of the entire locus identified 33 segmental duplications. CONCLUSIONS: We show that at least one of these segmental duplications, which borders the proximal breakpoint located within the NF1 intron 1 in five atypical deletions, might represent a novel hot spot for deletions. Our array constitutes a novel and reliable tool offering significantly improved diagnostics for this common disorder.

Methodological issues in longitudinal studies: vestibular schwannoma growth rates in neurofibromatosis 2.

Four longitudinal studies of vestibular schwannoma (VS) growth rates in neurofibromatosis 2 (NF2) have yielded very different results on the relationship of VS growth rates to age. The studies had different patient eligibility criteria, indices of VS growth rates, VS volumetric methods, and sample sizes. We reanalysed data from two of the longitudinal studies and used data from the population based United Kingdom NF2 Registry to determine the most likely reason for the different results and the actual relationship of VS growth rates to age. We found that the eligibility criterion in one study caused selection bias for slower growing VS. The proper interpretation of the results from the four studies is that VS growth rates in NF2 are highly variable but tend to decrease with increasing age. Clinical trials for VS in NF2 should focus on younger patients because VS growth rates tend to decrease with increasing age, and because faster growing VS are more likely to be excised with increasing age than slower growing VS.