An Update on Neurofibromatosis Type 1: Not Just Café-au-Lait Spots and Freckling. Part II. Other Skin Manifestations Characteristic of NF1. NF1 and Cancer

NEUROFIBROMATOSIS TYPE I AND ITS DIAGNOSTIC CRITERIA: A CLINICAL OBSERVATION

The aim - to consider the etiopathogenesis, the main clinical manifestations, diagnostic criteria of NF1, and present a clinical case from their practice. The paper analyzes the research findings in recent publications, focused on the studied issue using the methods of continuous sampling, synthesis and generalization, bibliosemantic evaluation and content analysis. In order to attract the attention of family physicians, neurologists, dermatologists, ophthalmologists, surgeons and other specialists, we present our own clinical observation of NF1. The patient was examined using the methods of neurological examination, as well as other laboratory and instrumental methods of research. Early diagnosis and medical examination of patients with NF1 is crucial for predicting and improving the quality of life of patients. NF1 is a complex disease where the cooperation of doctors of different specialties is important. A favorable prognosis for patients is associated with the possibility of early diagnosis of malignant transformation and timely treatment.

New Model Systems and the Development of Targeted Therapies for the Treatment of Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheath Tumors

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.