Nerve sheath tumors can be a significant cause of morbidity for many patients. These include benign tumors such as schwannomas, diffuse and plexiform neurofibromas, and atypical neurofibromas, as well as the aggressive soft tissue sarcoma known as the malignant peripheral nerve sheath tumor (MPNST). Nerve sheath tumors occur sporadically and in the context of the clinical neuro-genetic tumor predisposition syndromes neurofibromatosis type 1 (NF1) and type 2 (NF2). Historically, the mainstay of treatment for nerve sheath tumors has been surgery. However, for both benign and malignant nerve sheath tumors, there is a high recurrence rate, highlighting the pressing need for novel therapies. As we have entered the genomic era, the hope is that an improved understanding of the genetics, and therefore the biology, of these tumors will ultimately lead to therapies that result in better outcomes. In this Special Issue, we include both review articles and original research related to the genomic understanding and modeling of schwannomas, plexiform and diffuse neurofibromas, atypical neurofibromas, and malignant peripheral nerve sheath tumors as well as genomic methods being developed and applied to advance our understanding of these tumors.

Nerve sheath tumors can be a significant cause of morbidity for many patients. These include benign tumors such as schwannomas, diffuse and plexiform neurofibromas, and atypical neurofibromas, as well as the aggressive soft tissue sarcoma known as the malignant peripheral nerve sheath tumor (MPNST). Nerve sheath tumors occur sporadically and in the context of the clinical neuro-genetic tumor predisposition syndromes neurofibromatosis type 1 (NF1) and type 2 (NF2). Historically, the mainstay of treatment for nerve sheath tumors has been surgery. However, for both benign and malignant nerve sheath tumors, there is a high recurrence rate, highlighting the pressing need for novel therapies. As we have entered the genomic era, the hope is that an improved understanding of the genetics, and therefore the biology, of these tumors will ultimately lead to therapies that result in better outcomes. In this Special Issue, we include both review articles and original research related to the genomic understanding and modeling of schwannomas, plexiform and diffuse neurofibromas, atypical neurofibromas, and malignant peripheral nerve sheath tumors as well as genomic methods being developed and applied to advance our understanding of these tumors.

This volume offers an update of the clinical signs, diagnostic criteria (including molecular diagnosis) and targeted therapies for a particular type of genodermatosis, providing a handy and unique tool for early diagnosis. In recent years, our understanding of genodermatosis and neurocutaneous syndromes has increased, but although Type 1 Neurofibromatosis (NF1) is the most common neuroectodermal disorder and involves a large number of patients and medical disciplines, this syndrome remains underestimated, often misdiagnosed thus leading to inaccurate treatment. The literature on the molecular and pathogenetic aspects is ample, but current clinical approaches, classification, diagnostic criteria and treatment protocols are outdated, creating difficulties in early diagnosis and treatment. As such, a chapter is devoted renewing current diagnostic criteria; it includes clinical and molecular data, to offer a sound, updated discussion basis for a consensus conference. NF1 is a “time-dependent” disorder, meaning that the onset of clinical signs are closely linked to patient age and the book discusses this particularly neglected aspect extensively, as well as the latest molecular diagnosis techniques, which are highly sensitive have not been included in the diagnostic criteria. It also explains the role of the RAS-MAPK pathway and genotype-phenotype correlations. In addition it explores new concepts concerning the pathogenesis of neurofibromas and other hamarthomas and their relevance for a modern therapeutical approach with targeted molecular drugs, as well as newly discovered aspects of NF1 in all internal organs, together with their diagnostic counterparts. A chapter on mosaic neurofibromatosis is also included. There is a particular focus on differential diagnosis (i.e. other diseases with café-au-lait macules), and the recently described Legius syndrome will be presented directly by Prof Eric Legius. All chapters are easy-to-understand, up-to-date, comprehensive and concise tools and are intended for a wide range of professionals involved with genetic disorders of the skin and neurocutaneous diseases: dermatologists, pediatricians, neurologists, oncologists and general practitioners.

The goal of this research project is to identify molecular changes that are associated with the progression of a peripheral nerve sheath tumor (PNST) from benign to malignancy. Archival and prospectively acquired benign PNSTs and malignant PNSTs are collected, and molecular changes at the NF1 locus and throughout the genome are assessed. In addition, immunohistological evaluations of benign plexiform neurofibromas and malignant peripheral nerve sheath tumors are performed. We have begun preliminary analyses of immunohistochemical phenotypes of the tumors and genome-wide screen tetra-nucleotide screen for allelic imbalance, as a marker for accumulation of somatic mutations in PNSTs.

Neurofibromatosis type 1 (NF1), caused by mutational inactivation of the NF1 tumour suppressor gene, is one of the most common dominantly inherited human disorders, affecting 1 in 3000 individuals worldwide. This book presents in concise fashion, but as comprehensively as possible, our current state of knowledge on the molecular genetics, molecular biology and cellular biology of this tumour predisposition syndrome. Written by internationally recognized experts in the field, the 44 chapters that constitute this edited volume provide the reader with a broad overview of the clinical features of the disease, the structure and expression of the NF1 gene, its germ line and somatic mutational spectra and genotype-phenotype relationships, the structure and function of its protein product (neurofibromin), NF1 modifying loci, the molecular pathology of NF1-associated tumours, animal models of the disease, psycho-social aspects and future prospects for therapeutic treatment.

The goal of this project is to identify genes involved in the malignant transformation of neurofibromas to malignant peripheral nerve sheath tumors using expression profiling and array-based comparative genomic hybridization. The significance of the genes will be validated on much larger numbers of cases using antibodies and in situ hybridization probes on tissue microarrays (TMAs). Genes will be further studied in in vitro experiments using cell lines from nerve sheath tumors. While the grant starting date was on Nay 1, 2003 authorization to work with human subjects was not obtained until April 1, 2004. Therefore this "annual report" will only describe the actual work performed in April 2004. Nevertheless the following progress has been made in the past year: 1. The number of cases of nerve sheath tumors available will be more than sufficient to perform the first aim of this study. 2. We have started to run expression profiling and gene microarrays on a number of nerve sheath tumors and since April 1, 2004 have analyzed six malignant peripheral nerve sheath tumors and five schwannomas. 3. We have gained much experience with in situ hybridization on TMAs. This experience will enormously benefit this project.

Tumors involving peripheral nerves may be extremely challenging lesions to diagnose and treat. In order to optimize their management, physicians should have a thorough knowledge of peripheral nerve anatomy and pathology (both gross and microscopic), as well as familiarity with microsurgical techniques and intraoperative neurophysiological recording. This compendium deals with all aspects of tumors affecting peripheral nerves, from diagnosis to treatment; the topics it addresses range from epidemiology, anatomy, physiology, pathology, and clinical diagnosis to electrophysiology, imaging, genetic/cytomolecular aspects. Surgical approaches, biopsies and resection of various benign, malignant and pseudo-tumoral lesions, plexus tumors (both brachial and lumbosacral), and adjunctive treatment modalities and pain-related issues are described in detail. The book is intended not only for neurosurgeons, hand surgeons, plastic and orthopedic surgeons new to the field, but also for seasoned specialists who wish to update their knowledge with new insights based on robust experimental and clinical material. In addition, it will be a helpful tool for general and oncological surgeons who are sometimes faced with the treatment of mass lesions that may be potential nerve tumors, and for all practitioners who are engaged in the arduous struggle to bring relief to patients affected by these lesions.