The wide variety of clinical manifestations of the genetic syndrome neurofibromatosis type 1 (NF1) are driven by overactivation of the RAS pathway. Mitogen-activated protein kinase kinase inhibitors (MEKi) block downstream targets of RAS. The recent regulatory approvals of the MEKi selumetinib for inoperable symptomatic plexiform neurofibromas in children with NF1 have made it the first medical therapy approved for this indication in the United States, the European Union, and elsewhere. Several recently published and ongoing clinical trials have demonstrated that MEKi may have potential benefits for a variety of other NF1 manifestations, and there is broad interest in the field regarding the appropriate clinical use of these agents. In this review, we present the current evidence regarding the use of existing MEKi for a variety of NF1-related manifestations, including tumor (neurofibromas, malignant peripheral nerve sheath tumors, low-grade glioma, and juvenile myelomonocytic leukemia) and non-tumor (bone, pain, and neurocognitive) manifestations. We discuss the potential utility of MEKi in related genetic conditions characterized by overactivation of the RAS pathway (RASopathies). In addition, we review practical treatment considerations for the use of MEKi as well as provide consensus recommendations regarding their clinical use from a panel of experts.

Neurofibromatosis type 1 (NF1) is an autosomal dominant neoplastic disease caused by mutations in the NF1 gene and one of the most challenging diseases to treat. Patients have a characteristic phenotype with neurofibromas as the main features in different forms, including numerous cutaneous neurofibromas, plexiform neurofibromas involving the primary nerves, or malignant peripheral nerve sheath tumors with a very short survival period after malignant transformation. NF1 patients also suffer from multi-system involvement, with a high rate of deformity and disability, making complete surgical resection more difficult. Currently, there is no consensus on the diagnosis and treatment of NF1 in China, and different disciplines have different understandings of NF1. Multidisciplinary systematic evaluations and cooperative treatments are the keys to improve the treatment, quality of life, and prognosis of NF1 patients. In 2020, the Department of Plastic Surgery of the Ninth People\'s Hospital of Shanghai Jiaotong University School of Medicine led the establishment of the first multi-center collaboration group for NF1 in China. Furthermore, the group had worked with renowned experts from the various departments including surgical oncology, medical oncology, dermatology, reproductive medicine, et al. in China to formulate the \"Expert consensus on diagnosis and management of neurofibromatosis type 1 (2021 edition)\", aiming to promote standardized and homogeneous treatment covering the whole life cycle of NF1 patients and improve the treatment level and outcome of NF1 patients in China.
Ⅰ型神经纤维瘤病（neurofibromatosis type 1，NF1）是NF1基因突变引起的常染色体显性遗传性肿瘤性疾病，是目前医学诊疗的重点和难点之一。患者病变以神经纤维瘤为特征性表型，其中皮肤型神经纤维瘤数量大，丛状神经纤维瘤累及主干神经，恶变后的恶性外周神经鞘瘤生存期极短。同时NF1患者伴有多系统累及，疾病致畸率、致残率高，手术难以完整切除，治疗难度大。目前中国尚缺乏对于NF1的诊疗共识，不同学科对NF1的疾病认识不同，诊疗存在差异。多学科系统评估、合作诊疗是提高NF1患者治疗水平、生存质量及改善疾病预后等的关键。2020年由上海交通大学医学院附属第九人民医院整复外科牵头成立了中国首个 NF1 多中心治疗协作组，并进一步联合国内肿瘤外科、肿瘤内科、皮肤科、生殖医学科等学科的知名专家，共同撰写了《Ⅰ型神经纤维瘤病临床诊疗专家共识（2021版）》，旨在推进覆盖NF1患者全生命周期的规范化、同质化诊疗，提高中国NF1的诊疗水平和治疗效果。.