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Concept: Neurofibromatosis

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Background Effective medical therapies are lacking for the treatment of neurofibromatosis type 1-related plexiform neurofibromas, which are characterized by elevated RAS-mitogen-activated protein kinase (MAPK) signaling. Methods We conducted a phase 1 trial of selumetinib (AZD6244 or ARRY-142886), an oral selective inhibitor of MAPK kinase (MEK) 1 and 2, in children who had neurofibromatosis type 1 and inoperable plexiform neurofibromas to determine the maximum tolerated dose and to evaluate plasma pharmacokinetics. Selumetinib was administered twice daily at a dose of 20 to 30 mg per square meter of body-surface area on a continuous dosing schedule (in 28-day cycles). We also tested selumetinib using a mouse model of neurofibromatosis type 1-related neurofibroma. Response to treatment (i.e., an increase or decrease from baseline in the volume of plexiform neurofibromas) was monitored by using volumetric magnetic resonance imaging analysis to measure the change in size of the plexiform neurofibroma. Results A total of 24 children (median age, 10.9 years; range, 3.0 to 18.5) with a median tumor volume of 1205 ml (range, 29 to 8744) received selumetinib. Patients were able to receive selumetinib on a long-term basis; the median number of cycles was 30 (range, 6 to 56). The maximum tolerated dose was 25 mg per square meter (approximately 60% of the recommended adult dose). The most common toxic effects associated with selumetinib included acneiform rash, gastrointestinal effects, and asymptomatic creatine kinase elevation. The results of pharmacokinetic evaluations of selumetinib among the children in this trial were similar to those published for adults. Treatment with selumetinib resulted in confirmed partial responses (tumor volume decreases from baseline of ≥20%) in 17 of the 24 children (71%) and decreases from baseline in neurofibroma volume in 12 of 18 mice (67%). Disease progression (tumor volume increase from baseline of ≥20%) has not been observed to date. Anecdotal evidence of decreases in tumor-related pain, disfigurement, and functional impairment was observed. Conclusions Our early-phase data suggested that children with neurofibromatosis type 1 and inoperable plexiform neurofibromas benefited from long-term dose-adjusted treatment with selumetinib without having excess toxic effects. (Funded by the National Institutes of Health and others; ClinicalTrials.gov number, NCT01362803 .).

Concepts: Signal transduction, Brain tumor, Magnetic resonance imaging, Neurology, Area, Neurofibromatosis, Neurofibroma, Dermal and subcutaneous growths

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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 (Nf1fl/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.

Concepts: Gene, Cancer, Oncology, Action potential, Enzyme inhibitor, Neurofibromatosis, Malignant peripheral nerve sheath tumor, Nerve sheath tumor

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A 62-year-old female with neurofibromatosis type 1 (NF1; also von Recklinghausen’s disease) was diagnosed with a giant, thick-walled tubular mass, mainly located in the right abdominal area on computed tomography, following an examination for intermittent abdominal pain and increasing abdominal distension. According to the clinical manifestations and imaging features, the giant tubular mass was considered most likely to be a dilated fallopian tube associated with infection, while the possibility of obstructed bowel loops was excluded. However, the subsequent laparotomy revealed a giant appendix, caused by a large neurofibroma in the root region of the appendix, which occluded the lumen. Neurofibroma of the appendix is extremely rare, even in patients with NF1. To the best of our knowledge, only three such cases have previously been reported in the English literature to date.

Concepts: Neurology, Abdominal pain, Bowel obstruction, Neurofibromatosis type I, Neurofibromatosis, Abdominal distension, Friedrich Daniel von Recklinghausen, Café au lait spot

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Neurofibromatosis type 1 (NF1) is a common genetic disease that predisposes 30-50 % of affected individuals to develop plexiform neurofibromas. We found that macrophage infiltration of both mouse and human neurofibromas correlates with disease progression. Macrophages accounted for almost half of neurofibroma cells, leading us to hypothesize that nerve macrophages are inflammatory effectors in neurofibroma development and/or growth. We tested the effects of PLX3397, a dual kit/fms kinase inhibitor that blocks macrophage infiltration, in the Dhh-Cre; Nf1 ( flox/flox ) mouse model of GEM grade I neurofibroma. In mice aged 1-4 months, prior to development of nerve pathology and neurofibroma formation, PLX3397 did not impair tumor initiation and increased tumor volume compared to controls. However, in mice aged 7-9 months, after tumor establishment, a subset of mice demonstrating the largest reductions in macrophages after PLX3397 exhibited cell death and tumor volume regression. Macrophages are likely to provide an initial line of defense against developing tumors. Once tumors are established, they become tumor permissive. Macrophage depletion may result in impaired tumor maintenance and represent a therapeutic strategy for neurofibroma therapy.

Concepts: Cancer, Death, Effect, Apoptosis, Neurology, Neurofibromatosis type I, Neurofibromatosis, Neurofibroma

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OBJECTIVES: Neurofibromatosis 1 (NF1), NF2, and schwannomatosis are characterized by a predisposition to develop multiple neurofibromas and schwannomas. Currently, there is no blood test to estimate tumor burden in patients with these disorders. We explored whether S100β would act as a biomarker of tumor burden in NF since S100β is a classic immunohistochemical marker of astrocytes, oligodendrocytes and Schwann cells and a small study showed S100β concentrations correlate with the volume of vestibular schwannomas. Design and Methods We calculated whole-body tumor burden in subjects with NF1, NF2, and schwannomatosis using whole-body MRI (WBMRI) and measured the concentration of S100β in plasma using ELISA. We used chi-square tests and Spearman rank correlations to test the relationship between S100β levels and whole-body tumor burden. RESULTS: 127 consecutive patients were enrolled in the study (69 NF1 patients, 28 NF2 patients, and 30 schwannomatosis patients). The median age was 40years, 43% were male, median whole-body tumor volume was 26.9ml. There was no relationship between the presence of internal tumors and the presence of detectable S100β in blood for the overall group or for individual diagnoses (p>0.05 by chi-square for all comparisons). Similarly, there was no correlation between whole-body tumor volume and S100β concentration for the overall group or for individual diagnoses (p>0.05 by Spearman for all comparisons). CONCLUSIONS: Plasma S100β is not a useful biomarker for tumor burden in the neurofibromatoses. Further work is needed to identify a reliable biomarker of tumor burden in NF patients.

Concepts: Blood, Spearman's rank correlation coefficient, Neurology, Non-parametric statistics, Correlation and dependence, Pearson product-moment correlation coefficient, Neurofibromatosis, Neurofibroma

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About 50% of all malignant peripheral nerve sheath tumors (MPNSTs) arise as neurofibromatosis type 1 associated lesions. In those patients malignant peripheral nerve sheath tumors are thought to arise through malignant transformation of a preexisting plexiform neurofibroma. The molecular changes associated with this transformation are still poorly understood. We sought to test the hypothesis that dysregulation of expression of kinases contributes to this malignant transformation. We analyzed expression of all 519 kinase genes in the human genome using the nanostring nCounter system. Twelve cases of malignant peripheral nerve sheath tumor arising in a background of preexisting plexiform neurofibroma were included. Both components were separately sampled. Statistical analysis compared global changes in expression levels as well as changes observed in the pairwise comparison of samples taken from the same surgical specimen. Immunohistochemical studies were performed on tissue array slides to confirm expression of selected proteins. The expression pattern of kinase genes can separate malignant peripheral nerve sheath tumors and preexisting plexiform neurofibromas. The majority of kinase genes is downregulated rather than overexpressed with malignant transformation. The patterns of expression changes are complex without simple recurring alteration. Pathway analysis demonstrates that differentially expressed kinases are enriched for kinases involved in the direct regulation of mitosis, and several of these show increased expression in malignant peripheral nerve sheath tumors. Immunohistochemical studies for the mitotic regulators BUB1B, PBK and NEK2 confirm higher expression levels at the protein level. These results suggest that the malignant transformation of plexiform neurofibroma is associated with distinct changes in the expression of kinase genes. The patterns of these changes are complex and heterogeneous. There is no single unifying alteration. Kinases involved in mitotic regulation are particularly enriched in the pool of differentially expressed kinases. Some of these are overexpressed and are therefore possible targets for kinase inhibitors.Modern Pathology advance online publication, 1 February 2013; doi:10.1038/modpathol.2012.242.

Concepts: Gene expression, Cancer, Oncology, Human genome, Neurofibromatosis, Malignant peripheral nerve sheath tumor, Nerve sheath tumor, Neurofibroma

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We encountered a rare case of intraventricular ganglioglioma associated with neurofibromatosis type 1. A 42-year-old woman presented with a feeling of heaviness of the head and dizziness. She was diagnosed with neurofibromatosis type 1 because she had multiple subcutaneous neurofibromas and café au lait spots. On admission, she deteriorated slightly(Japan Coma Scale 1)and suffered from cognitive dysfunction and right hemiparesis. A computed tomography(CT)scan showed that she had an obstructed hydrocephalus with a long and circular mass lesion, 2cm in diameter, in the anterior horn of the left lateral ventricle. The mass showed low signal intensity(SI)on the T1-weighted image(WI), heterogeneous high SI on the T2-WI, and dense enhancement on a Gd-DTPA contrast MRI, extending from the head of the left caudate nucleus to the lateral ventricle. The patient underwent an urgent operation via an anterior transcallosal approach because of an obstructed hydrocephalus. The tumor was removed in its entirety, including its origin at the caudate head. The pathological diagnosis was a ganglioglioma grade 1 according with the classification of the World Health Organization. Here we describe this case and discuss the rare association between gangliogliomas and neurofibromatosis type 1.

Concepts: Brain, Oncology, Cerebral cortex, Neurology, Ventricular system, Neurofibromatosis, Neurofibroma, Lateral ventricles

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BACKGROUND Pancreatic endocrine tumors (PETs) are rare and can occur as part of neurofibromatosis type 1 (NF1). Gastrinomas are functional PETs that are rarely associated with NF1. Only two cases of their occurrence have been reported in the literature. CASE REPORT A 28-year-old woman was admitted for further evaluation of epigastric soreness, heartburn, nausea, vomiting, diarrhea, and a significant weight loss. Physical examination was remarkable for cutaneous findings (axillary freckling and multiple café-au-lait spots) as well as neurofibromas (dermal, plexiform). A diagnosis of NF1 was confirmed. Esophagogastroduodenoscopy (EGD) revealed multiple ulcers in the duodenum and the upper jejunum. A fasting gastrin level exceeded ten times the normal limit. An abdominal multi-slice 128 computed tomography (CT) scan revealed an oval mass of 26 mm in diameter adjacent to the second section of the duodenum. The patient was examined carefully to rule out multiple endocrine neoplasia type 1 (MEN1). Surgical resection was performed and a gastrinoma, causing Zollinger-Ellison syndrome (ZES), was diagnosed by histological examinations of the extirpated mass. The serum gastrin level decreased to normal limits shortly after surgery. Continuous follow-up revealed that the symptoms and the EGD findings completely resolved without recurrences. CONCLUSIONS Although NF1 has common skeletal, visual, neurological, and cardiovascular complications, it also has a rare association with duodenal or pancreatic gastrinomas. Vigilance for this possible association is important to promote timely and careful management to help eliminate serious and potentially life-threatening complications.

Concepts: Cancer, Endocrinology, Neurofibromatosis type I, Multiple endocrine neoplasia, Neurofibromatosis, Zollinger-Ellison syndrome, Gastrin, Gastrinoma

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The earliest examples of neurofibromatosis (in this case type 1, NF1) can be traced in the Ebers Papyrus (Ancient Egypt, 1.500 B.C.), in a Hellenistic statuette (Smyrna, 323 B.C.), in the coinage of the Parthians kings (247 B.C.) and in some 13th century monks' drawings. These earlier examples are somewhat less well defined as compared to the most recent better defined reports credited as having NF1 including an Inca child mummy (1480-1650 AD), Ulisse Aldrovandi’s homuncio (“Monstrorum Historia”, 1592 A.D.) with mosaic NF1 or the illustrations seen in the 18th century “Buffon’s Histoire Naturelle” and “Cruveilhier’s Anatomie Pathologique du Corps Human”. The first English language report on NF1 was made by Akenside in 1768 and the first systematic review by Robert William Smith in 1849, while Virchow’s pupil, Friedrich Daniel von Recklinghausen, in 1882, was the first to understand the origin of skin tumors and to name them neurofibromas. The touching story of Joseph C. Merrick (the “Elephant man,” (who had Proteus syndrome and not NF1), in 1884, played an important role in the later misconception of NF1, as did the novel by Vicotr Hugo on the hunchback Quasimodo. The studies by van der Hoeve (1921), Yakovlev and Guthrie (1931), and Van Bogaert (1935), categorized “von Recklinghausen’s” neurofibromatosis among the phakomatoses and the neurocutaneous syndromes. The first known mention of an acoustic neuroma (at autopsy) is attributed to Eduard Sandifort (1777 AD) while John H. Wishart made the earliest autoptic description of neurofibromatosis type 2 (NF2), in 1822, in a 21-year-old man with bilateral acoustic neuromas, who manifested signs since his infancy (Wishart subtype NF2). Smith likely described the first case of schwannomatosis in 1849. Older, Virchow, von Recklinghausen, and Verocay first classified “neuromas” and Masson and Penfield first used the word “schwannoma” taking it from Theodore Schwann’s works. In 1903 Henneberg and Koch described NF2 in detail. Young, Eldridge, and Gardner, in the late ‘70, established NF2 as a distinct familial entity (Gardner subtype NF2). Schwannomatosis, the late entry of the different forms of neurofibromatosis, was credited in the middle '90.

Concepts: Neurology, Neurofibromatosis type I, Ancient Egypt, Neurofibromatosis, Schwannoma, Friedrich Daniel von Recklinghausen, Joseph Merrick, Ulisse Aldrovandi

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The current study was designed to determine the risk of cancer in patients with neurofibromatosis type 1 (NF1) by cancer type, age, and sex with unprecedented accuracy to be achieved by combining two total population-based registers.

Concepts: The Current, Neurofibromatosis type I, Neurofibromatosis, Café au lait spot