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Neurofibromatosis type 1 (NF1) is associated with below average writing achievement. However, little is known about specific aspects of written language impacted by NF1, changes in writing over time, and associations between cognitive aspects of the NF1 phenotype and writing. At three timepoints over six years, children with NF1 and plexiform neurofibromas (PNs) completed Woodcock-Johnson tests of writing mechanics (Spelling, Punctuation & Capitalization, handwriting), written expression of ideas (Writing Samples), writing speed (Writing Fluency), and tests of general cognitive ability, executive function, memory, and attention. Children ( N  = 76, mean age = 12.8 ± 3.4 years) completed at least one baseline writing subtest. Overall writing scores were in the Average range ( M  = 93.4, SD  = 17.4), but lower than population norms ( p  = 0.002). Scores were highest on Writing Samples ( M  = 95.2, SD  = 17.3), and lowest for Punctuation & Capitalization ( M  = 87.9, SD  = 18.8, p  = 0.034). Writing scores were mostly stable over time. Nonverbal reasoning was related to some tests of writing mechanics and written expression of ideas. Short-term memory and inattention explained additional variance in Writing Samples and Spelling. Poor handwriting was associated with writing content beyond the impact of cognitive factors. Children with NF1 and PNs may benefit from early screening and writing support. Interventions should address the contribution of both cognitive and handwriting difficulties in written language.

Aim: To provide a comprehensive characterization of verbal learning and memory (VLM) abilities in youth with neurofibromatosis type 1 (NF1) and plexiform neurofibromas (PNs) and to evaluate disease severity as a predictor of VLM functioning over time., Method: As part of a longitudinal natural history study, youth with NF1 and PNs were administered repeat neuropsychological assessments, including measures of VLM and ratings of NF1 disease severity completed by a medical professional. This sub-study analyzed data from 89 patients (M age baseline  = 13.1, SD = 4.3 years, range 6-24 years) who had completed tests of VLM abilities and verbal attention at either baseline and/or 36 months., Results: VLM scores across the sample fell predominantly within the average range of functioning at both time points. However, relative to peers with mild NF1 disease severity, youth with moderate/severe NF1 disease showed lower functioning across multiple VLM domains at 36 months, even after controlling for the effects of verbal attention., Interpretation: Exclusive use of overall domain scores does not fully characterize VLM functioning in youth with NF1 and PNs. Additionally, children and adolescents with more severe NF1 disease should be monitored more closely for verbal memory challenges and targeted for interventions., (© 2022 Published by Elsevier Ltd on behalf of European Paediatric Neurology Society.)

Neurofibromatosis type 1 (NF1) is a genetic syndrome affecting about 1 in 3500 individuals; many of those affected have plexiform neurofibroma (pNF) tumors and associated symptoms and complications. Furthermore, learning and attention problems, as well as deficits in adaptive functioning, are common, often beginning in early childhood. This study aimed to describe adaptive functioning and to examine relationships between adaptive functioning and cognitive and academic variables and level of independence among adolescents and young adults (AYA) with NF1 and pNF tumors. Fifty-five AYA aged 16-31 years participated in a series of neuropsychological evaluations while parents completed the Vineland Adaptive Behavior Scales (VABS-II) as part of a larger natural history study. Over one-third (35%) of AYA were neither in school nor employed. Mean VABS-II daily living and socialization scores were low average while mean Verbal and Performance IQ scores were average. VABS-II scores were positively correlated with processing speed, executive functioning, and working memory scores. Verbal IQ was the only significant predictor of work/school status. Identification of the correlates and predictors of adaptive functioning and life achievement can help guide healthcare providers with the early identification of risk factors and possible areas for intervention., (© 2021 Wiley Periodicals LLC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.)

Individuals with neurofibromatosis type 1 (NF1) and plexiform neurofibromas (PNs) can experience chronic pain. Previous research has examined the relationship between heart rate variability (HRV) and persistent pain. HRV is an index of autonomic nervous system functioning, and reflects the variability in time elapsed between heartbeats. Patients with chronic pain tend to exhibit lower HRV, which has been associated with poor adaptability, or psychological flexibility, to stress. The aim of the current study was to examine relationships between HRV, psychological flexibility, and pain in a sample of adolescents and young adults (AYAs) with NF1 and PNs. AYA participants (n = 40) 16 to 34 years of age with NF1 completed baseline measures of pain and psychological functioning, and underwent a 5-minute electrocardiogram (ECG). A subset of 20 participants completed follow-up questionnaires and a second ECG 8 weeks later. Spectral analyses of ECGs yielded a measure of high-frequency heart rate variability (HF-HRV). Baseline correlations revealed that lower HF-HRV is related to greater inflexibility and more pain interference, but not pain intensity. Moreover, psychological inflexibility significantly mediated the relationship between HF-HRV and pain interference. Finally, regression models indicated that baseline psychological inflexibility is a significant predictor of HF-HRV at follow-up and, separately, that baseline HF-HRV significantly predicted pain intensity at follow-up. These findings suggest complex mind-body processes in the experience of pain in NF1, which have not been studied previously. Implications for pain-related interventions and future research are discussed., (© 2018 World Institute of Pain.)

Patients with neurofibromatosis 1 (NF1) develop multiple neurofibromas, with 8% to 15% of patients experiencing malignant peripheral nerve sheath tumor (MPNST) during their lifetime. Prediction of transformation, typically from plexiform neurofibroma, is clinically and histologically challenging. In this overview, after a consensus meeting in October 2016, we outline the histopathologic features and molecular mechanisms involved in the malignant transformation of neurofibromas. Nuclear atypia alone is generally insignificant. However, with atypia, loss of neurofibroma architecture, high cellularity, and/or mitotic activity >1/50 but <3/10 high-power fields, the findings are worrisome for malignancy. We propose the term "atypical neurofibromatous neoplasms of uncertain biologic potential (ANNUBP)" for lesions displaying at least 2 of these features. This diagnosis should prompt additional sampling, clinical correlation, and possibly, expert pathology consultation. Currently, such tumors are diagnosed inconsistently as atypical neurofibroma or low-grade MPNST. Most MPNSTs arising from neurofibromas are high-grade sarcomas and pose little diagnostic difficulty, although rare nonnecrotic tumors with 3-9 mitoses/10 high-power fields can be recognized as low-grade variants. Although neurofibromas contain numerous S100 protein/SOX10-positive Schwann cells and CD34-positive fibroblasts, both components are reduced or absent in MPNST. Loss of p16/CDKN2A expression, elevated Ki67 labeling, and extensive nuclear p53 positivity are also features of MPNST that can to some degree already occur in atypical neurofibromatous neoplasms of uncertain biologic potential. Complete loss of trimethylated histone 3 lysine 27 expression is potentially more reliable, being immunohistochemically detectable in about half of MPNSTs. Correlated clinicopathological, radiologic, and genetic studies should increase our understanding of malignant transformation in neurofibromas, hopefully improving diagnosis and treatment soon., (Published by Elsevier Inc.)

Neurofibromatosis type 1 (NF1) is a common tumor-predisposition disorder due to germline mutations in the tumor suppressor gene NF1. A virtually pathognomonic finding of NF1 is the plexiform neurofibroma (PN), a benign, likely congenital tumor that arises from bi-allelic inactivation of NF1. PN can undergo transformation to a malignant peripheral nerve sheath tumor, an aggressive soft-tissue sarcoma. To better understand the non-NF1 genetic contributions to PN pathogenesis, we performed whole-exome sequencing, RNASeq profiling and genome-wide copy-number determination for 23 low-passage Schwann cell cultures established from surgical PN material with matching germline DNA. All resected tumors were derived from routine debulking surgeries. None of the tumors were considered at risk for malignant transformation at the time; for example, there was no pain or rapid growth. Deep (~500X) NF1 exon sequencing was also conducted on tumor DNA. Non-NF1 somatic mutation verification was performed using the Ampliseq/IonTorrent platform. We identified 100% of the germline NF1 mutations and found somatic NF1 inactivation in 74% of the PN. One individual with three PNs had different NF1 somatic mutations in each tumor. The median number of somatic mutations per sample, including NF1, was one (range 0-8). NF1 was the only gene that was recurrently somatically inactivated in multiple tumors. Gene Set Enrichment Analysis of transcriptome-wide tumor RNA sequencing identified five significant (FDR<0.01) and seven trending (0.01⩽FDR<0.02) gene sets related to DNA replication, telomere maintenance and elongation, cell cycle progression, signal transduction and cell proliferation. We found no recurrent non-NF1 locus copy-number variation in PN. This is the first multi-sample whole-exome and whole-transcriptome sequencing study of NF1-associated PN. Taken together with concurrent copy-number data, our comprehensive genetic analysis reveals the primacy of NF1 loss as the driver of PN tumorigenesis.

Neurofibromatosis type 1 (NF1) is an autosomal dominant genetic disorder affecting about 1 in 3,500 individuals. Chronic pain is commonly reported among individuals with NF1 and plexiform neurofibroma tumors (PNs). Acceptance and Commitment Therapy (ACT), an empirically supported method for addressing chronic pain, helps individuals re-focus on valued relationships and activities. This pilot study investigated the feasibility and preliminary efficacy of a brief ACT workshop in the NF1 population. Eligible participants included adolescents and young adults (AYA; 12-21 years) with NF1 and chronic pain that interfered with daily functioning and their parents. Patients and parents completed baseline measures of pain interference, pain intensity, functional disability, pain acceptance, depression, and anxiety. Then, AYA and parents participated separately in a 2-day small-group ACT workshop. A telephone booster session occurred 1 month post-intervention. Three-month post-treatment measures were completed by mail. Ten adolescents (4 males; M age = 16.9 years) and seven parents provided baseline and 3-month data. Mean satisfaction with the study was moderate to high (3.9 for patients and 4.6 for parents on a 1-5 scales). Patients and parents reported significant declines in patients' pain interference at 3 months post-treatment. Patient-reported pain intensity significantly declined from baseline to 3 months. Parents reported marginally greater acceptance of their child's pain. No changes emerged in functional ability or mood. Preliminary findings suggest that a brief ACT group intervention is feasible and may help AYA with NF1 and PNs cope with their chronic pain, although larger randomized studies are needed to confirm treatment efficacy. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Youth with neurofibromatosis type 1 (NF1) have multiple, complex symptoms associated with physical, social-emotional, and cognitive difficulties. In addition, caring for a child with NF1 can be extremely challenging for parents. Since research with other chronic illness populations suggests that social support, including internet support groups (ISGs), can be beneficial, this survey study aimed to determine the attitudes and preferences of adolescents and young adults with NF1 and parents of a child with NF1 regarding ISGs. Thirty patients and 30 caregivers completed a 24-item survey about ISGs. Many patients and parents are not aware of any ISGs for NF1, but are interested in using one in the future for a variety of reasons, including to get answers to their questions about NF1, to find out about research studies, and to discuss problems and concerns about NF1. Specific concerns of interest include physical, social-emotional, and cognitive aspects of NF1. ISGs have potential as a social support intervention within the NF1 community. ISGs for the NF1 population should include patients with NF1 (or parents of children with NF1) as well as a health professional, and both chat rooms and discussion boards likely would be well-received.

Neurofibromatosis type 1 (NF1) patients develop benign neurofibromas and malignant peripheral nerve sheath tumors (MPNST). These incurable peripheral nerve tumors result from loss of NF1 tumor suppressor gene function, causing hyperactive Ras signaling. Activated Ras controls numerous downstream effectors, but specific pathways mediating the effects of hyperactive Ras in NF1 tumors are unknown. We performed cross-species transcriptome analyses of mouse and human neurofibromas and MPNSTs and identified global negative feedback of genes that regulate Ras/Raf/MEK/ERK signaling in both species. Nonetheless, ERK activation was sustained in mouse and human neurofibromas and MPNST. We used a highly selective pharmacological inhibitor of MEK, PD0325901, to test whether sustained Ras/Raf/MEK/ERK signaling contributes to neurofibroma growth in a neurofibromatosis mouse model (Nf1(fl/fl);Dhh-Cre) or in NF1 patient MPNST cell xenografts. PD0325901 treatment reduced aberrantly proliferating cells in neurofibroma and MPNST, prolonged survival of mice implanted with human MPNST cells, and shrank neurofibromas in more than 80% of mice tested. Our data demonstrate that deregulated Ras/ERK signaling is critical for the growth of NF1 peripheral nerve tumors and provide a strong rationale for testing MEK inhibitors in NF1 clinical trials.

Background: Individuals with Neurofibromatosis type 1 (NF1) are at risk for developing malignant peripheral nerve sheath tumors (MPNST), which frequently arise in preexisting plexiform neurofibromas (PN). Magnetic resonance imaging (MRI) with volumetric analysis and 18-fluorodeoxyglucose-positron emission tomography (FDG-PET) were utilized to monitor symptomatic nodular lesions., Procedure: Patients with NF1 and PN on a NCI natural history trial were monitored for total body tumor volume (TTV) using volumetric MRI. FDG-PET was performed in individuals with a nodular well-demarcated lesion ≥3 cm if they were growing, painful, or there was a prior history of MPNST (target lesions). Asymptomatic nodular lesions were evaluated as non-target lesions., Results: Fifteen patients (8m, 7f) median age of 18.3 years (range, 10-45 years) had a single target and non-target (n = 46) nodular lesions identified on MRI. Target lesions arose within (n = 8) or outside (n = 3) a PN, and all but 1 had increased FDG uptake. FDG uptake was increased in non-target lesions but to a lesser degree. FDG uptake in the surrounding PN was low, similar to background activity. Pathologic evaluation performed in 11 patients demonstrated neurofibroma (n = 6), atypical neurofibroma (n = 2) and malignancy (n = 3)., Conclusions: Nodular target lesions identified on MRI in individuals with NF1 and PN demonstrate increased FDG uptake similar to MPNST, but may be benign on biopsy. Nodular target lesions may be at greater risk for malignant transformation, but their biologic and clinical behavior has not been well studied. Careful longitudinal evaluation will be required to better understand the malignant potential of these lesions., (Copyright © 2012 Wiley Periodicals, Inc.)

Objective: This descriptive cross-sectional study aimed to determine how cognitive, disease, and environmental variables relate to social-emotional functioning in youth with NF1 and plexiform neurofibromas., Methods: Psychological assessments were administered to 53 children (mean age 12.4 years); parents and teachers completed the behavior assessment system for children-second edition (BASC-2). Disease severity was quantified by nurse-practitioner ratings and tumor burden, and parents completed a life events checklist to indicate environmental stressors., Results: Notable proportions of children scored in the at-risk/clinically significant ranges on several parent and teacher BASC-2 subscales including somatization, attention problems, depression, and withdrawal. Combinations of cognitive, disease, and environmental variables predicted scores on parent BASC-2 internalizing problems, behavior symptoms index, and Adaptive Skills composites., Conclusions: Cognitive, disease, and environmental variables relate to social-emotional outcomes in children with NF1. These youth may benefit from interventions targeting social skills, cognitive functioning, and adaptive ways of coping with NF1-related pain.

Objective: To describe the characteristics of children enrolled in treatment trials for neurofibromatosis type 1 (NF1)-related plexiform neurofibroma (PN), PN tumor burden, PN-related complications, and treatment outcomes and to highlight the differences between characteristics of children with NF1 vs children with cancers entered on early phase drug trials., Methods: Pre-enrollment characteristics and complications of PN were retrospectively analyzed in a cohort of 59 children with NF1-related PN treated on 1 of 7 clinical trials at the NIH between 1996 and 2007. Outcome was analyzed in a subset of 19 patients enrolled in phase I trials. Comparisons to children with cancer were made from a similar analysis performed recently., Results: The median age at enrollment was 8 years. The median PN volume was 555 mL. Most patients had no prior chemotherapy or radiation, but nearly half had previous surgery for PN. PN-associated complications and NF1 manifestations were common, including pain (53%), other tumors (18%), and hypertension (8%). Investigational drug therapy was well tolerated. A median of 10 treatment cycles was administered. Patients with NF1-related PN were younger, had better performance score, had less prior therapy, and remained on study longer than cancer patients., Conclusions: Children with NF1-related plexiform neurofibroma (PN) enrolled in clinical trials had large tumors with substantial morbidity. Clinical trials in these children provide information about drug tolerance, cumulative toxicity, and pharmacokinetics in a younger population than early phase pediatric cancer trials. This report may aid in the evaluation of the applicability of traditional pediatric cancer trial designs and endpoints for NF1-related PN.

Objective: To longitudinally analyze changes in plexiform neurofibroma (PN) volume in relation to age and body growth in children and young adults with neurofibromatosis type 1 and inoperable, symptomatic, or progressive PNs, using a sensitive, automated method of volumetric MRI analysis., Methods: We included patients 25 years of age and younger with PNs entered in a natural history study or in treatment trials who had volumetric MRI over > or =16 months., Results: We studied 49 patients (median age 8.3 years) with 61 PNs and a median evaluation period of 34 months (range 18 to 70). The PN growth rates varied among patients, but were constant within patients. Thirty-four patients (69%) experienced > or =20% increase in PN volume during the observation period. PN volume increased more rapidly than body weight over time (p = 0.026). Younger patients had the most rapid PN growth rate., Conclusions: Volume increase of plexiform neurofibromas is a realistic and meaningful trial endpoint. In most patients plexiform neurofibroma growth rate exceeded body growth rate. The youngest patients had the fastest plexiform neurofibroma growth rate, and clinical drug development should be directed toward this population. Age stratification for clinical trials for plexiform neurofibromas should be considered.

An automated technique for segmentation and volumetric measurement of plexiform neurofibromas (PN) in neurofibromatosis 1 using short T1-inversion recovery magnetic resonance images is presented. The algorithm described implements heuristics derived from human-based recognition of lesions. This technique combines region-based with boundary-based segmentation. Two observers, who performed semi-automated volume calculations and manual tracings to estimate tumor volume, validated this method on 9 PNs of different size and location. This automated method was reproducible (coefficient of variation 0.6-5.6%), yielded similar results to manual tumor tracings (R = 0.999) and will likely improve the ability to measure PNs in ongoing clinical trials.

Abstract Background To examine the natural growth dynamics of internal plexiform neurofibromas (PNs) in patients with neurofibromatosis 1 (NF1). Methods Two hundred and one NF1 patients underwent whole body MRI (WBMRI). Tumour burden was estimated volumetrically. Non-parametric Spearman’s rho correlation coefficients were used to analyse the relationship of growth rate to tumour volume and age. Chi-squared and Mann–Whitney U tests were used for analysing the association of tumour occurrence with sex or age. Chi-squared tests were used to analyse the association of tumour growth with age group. Results Seventy-one of 171 patients with serial WBMRI exams had internal PNs (median follow up 2.2 years [1.1 to 4.9 years]). Median whole body tumour volume was 86.4 mL [5.2 to 5878.5 mL]) with a median growth rate of 3.7%/year (−13.4 to 111%/year) that correlated with larger whole body tumour volume (PP=0.004). No new PNs developed in 273.0 patient-years among patients without tumours. Rate of new tumour development among patients with PNs was 0.6%/year (95% confidence interval 0.02 to 3.4%). Twenty-seven (13.5%) tumours increased significantly and were more frequent among children (PP Conclusion Children with NF1 and internal PNs are at risk for tumour growth. Most PNs grow slowly or not at all, and some decrease in size. New tumours are infrequent in NF1 patients with PNs and unlikely in patients without PNs.