Response to the BRAF/MEK inhibitors dabrafenib/trametinib in an adolescent with a BRAF V600E mutated anaplastic ganglioglioma intolerant to vemurafenib

Efficacy of BRAF V600E targeted therapies in brain tumors harboring the mutation has been shown in several case reports and is currently being studied in larger clinical trials. Monotherapy with vemurafenib has been associated with significant side effects, including rashes, papillomas, and squamous cell carcinomas. Here we describe an adolescent female with anaplastic ganglioglioma and significant skin reaction to vemurafenib with subsequent tumor response and tolerance to the BRAF/MEK inhibitor combination of dabrafenib and trametinib without recurrence of previous reaction.     

Successful Retreatment of a Child with a Refractory Brainstem Ganglioglioma with Vemurafenib

A child with brainstem ganglioglioma underwent subtotal resection and focal radiation. Magnetic resonance imaging confirmed tumor progression 6 months later. Another partial resection revealed viable BRAF V600E‐positive residual tumor. Vemurafenib (660 mg/m²/dose) was administered twice daily, resulting in >70% tumor reduction with sustained clinical improvement for 1 year. Vemurafenib was then terminated, but significant tumor progression occurred 3 months later. Vemurafenib was restarted, resulting in partial response. Toxicities included Grade I pruritus and Grade II rash. Vemurafenib was effectively crushed and administered in solution via nasogastric tube. We demonstrate benefit from restarting vemurafenib therapy.     

严重表型心- 面- 皮肤综合征2 例临床特征和基因突变分析

目的探讨心-面-皮肤综合征严重表型患儿的临床特征和基因变异。方法回顾分析2例具有心-面-皮肤综合征严重表型患儿的临床资料,以及高通量测序技术检测的基因分析结果。结果 2例男性患儿,生后即出现喂养困难及精神运动发育迟缓,除有颅面部和心脏畸形外,还伴喉气管畸形,均在6月龄内死亡。基因检测发现2例患儿的BRAF基因存在新生变异c.1783TC(p.F595L)、c.770AG(p.Q257R)。结论发现2例国内未见报道的BRAF基因变异致心-面-皮肤综合征严重表型患儿。     

Recent advances in Langerhans cell histiocytosis

The purpose of this review is to provide an updated overview of the pathogenesis and treatment of Langerhans cell histiocytosis (LCH). The pathogenesis of LCH remains obscure and the optimal treatment for LCH has not been established, although incremental progress has been made. Proinflammatory cytokines and chemokines are known to play a role in LCH, which suggests that LCH is an immune disorder. However, the oncogenic BRAF mutation is also detected in more than half of LCH patients, which suggests that LCH is a neoplastic disorder. Remaining major issues in the treatment of LCH are how to rescue patients who have risk‐organ involvement but do not respond to first‐line therapy, the optimal treatment for the orphan disease of multifocal adult LCH, and how to reduce and treat central nervous system‐related consequences, such as central diabetes insipidus and neurodegeneration. More research is needed to better understand the pathogenesis of this disease and to resolve the treatment issues.     

Langerhans cell histiocytosis in non‐twin siblings

Langerhans cell histiocytosis (LCH), which has unknown pathogenesis, can manifest as many kinds of signs and symptoms at any age. Although its genetic background has not been exactly identified, the familial clustering of this disease has been described in some reports. It is very uncommon, however, in siblings who are not monozygotic or dizygotic twins. Reported herein is a case of LCH in non‐twin siblings (younger sister and elder brother) who were diagnosed at 3.3 and 14.5 years of age, respectively, and successfully treated with chemotherapy, with BRAF V600E mutation status, and a brief review of the literature.     

Dramatic clinical and radiographic response to BRAF inhibition in a patient with progressive disseminated optic pathway glioma refractory to MEK inhibition

While clinical and radiographic responses to agents targeting the mitogen-activated protein kinases (MAPK) pathway have been repor-ted in pediatric low-grade gliomas (LGG), early phase trials indicate refractoriness to these medications in some of these patients. We report a patient with disseminated LGG with the BRAFV600E mutation, which was refractory to selumetinib, a MEK inhibitor, but subsequently showed immediate clinical and radiographic response to dabrafenib, a BRAF inhibitor, with sustained effect for 9 months prior to clinical progression. In LGGs, treatment resistance to one agent targeting the MAPK pathway might not imply refractoriness to other agents targeting this pathway.     

BRAF基因V600E突变在儿童朗格罕细胞组织细胞增生症中的临床意义

目的探讨单中心儿童朗格罕细胞组织细胞增生症(LCH)患者BRAF基因V600E突变情况及其临床意义。方法回顾性分析80例首都医科大学附属北京儿童医院2014年1月—2014年12月期间经病理诊断的LCH患者的临床资料,用二代基因测序的方法检测其病理标本及血浆中BRAF基因V600E突变。采用SPSS 18.0统计软件进行数据分析处理。结果本组研究中病理标本检测BRAF基因F600E突变的阳性率68%,血浆样本检测阳性率59%。其中双阳性42例(53%),双阴性15例(19%)。对血浆或病理阳性患者BRAF基因F600E突变与年龄、性别、临床分组、受累器官、早期治疗反应、复发进行相关性分析,血浆阳性组P值分别为:0.737,0.06,0.718,0.727,0.739,0.879;病理标本阳性组P值分别为:0.303,0.88,0.519,0.728,0.088,0.065,提示差异均无显著性。结论本组儿童LCH患者存在较高的BRAF基因V600E突变,提示部分患者组织细胞呈克隆性生长。该研究未发现BRAF基因F600E突变与LCH患者临床表现、治疗反应和预后的相关性,也许与本研究样本量少有关,仍有待于扩充样本量进一步研究。     

Targeted therapy for infants with diencephalic syndrome: A case report and review of management strategies

Young children with emaciation caused by a hypothalamic glioma are considered to have diencephalic syndrome (DS), which is often poorly controlled with conventional treatment. We describe an infant with DS whose tumor progressed following chemotherapy. Biopsy was performed for molecular testing and demonstrated a BRAF fusion. Treatment with the MEK inhibitor trametinib for 18 months resulted in reduction of tumor size, normalization of his weight curve, and marked neurodevelopmental improvement. Our results build on earlier reports of using targeted agents for low‐grade glioma, and we review the evolving management strategy for such patients in the era of precision medicine.     

Longitudinal mutational analysis of a cerebellar pilocytic astrocytoma recurring as a ganglioglioma

A cerebellar pilocytic astrocytoma (PA) in a child recurred first with a PA histology and then with features of a ganglioglioma (GG). Molecular genetic analyses of the tumors confirmed a BRAF V600E mutation in all. They also all harbored a T202M mutation in ERK1, a kinase downstream of BRAF that is implicated in glial versus neuronal differentiation. The GG sample contained several variants that were not present in the PA samples; in particular, it had a truncating mutation in MAP2. These findings not only underscore the role of BRAF as oncogenic driver but also suggest that other genes may influence tumor morphology.     

Novel activating BRAF fusion identifies a recurrent alternative mechanism for ERK activation in pediatric Langerhans cell histiocytosis

Langerhans cell histiocytosis (LCH) is an inflammatory myeloid neoplasm characterized by constitutive activation of extracellular signal‐regulated kinase (ERK). Genomic characterization has identified activating point mutations including mutually exclusive BRAFV600E and activating MAP2K1 mutations to be responsible for ERK activation in a majority of pediatric LCH patients. Here, we report the discovery of a novel BRAF kinase fusion, PACSIN2‐BRAF, in a child with multisystem LCH. This is the second reported case of an activating BRAF kinase fusion and indicates a recurrent pathologic mechanism. Genomic evaluation for activating kinase fusions should be strongly considered in pediatric LCH patients lacking more common mutations.     

儿童甲状腺乳头状癌 BRAF基因突变及临床意义

目的:研究儿童甲状腺乳头状癌 BRAF(V600E)基因突变情况及其临床意义。 方法:选取2012年1月至2016年12月天津医科大学肿瘤医院肿瘤组织库收集的儿童(≤18岁)甲状腺乳头状癌肿瘤组织标本,进行 BRAF(V600E)基因检测,分析 BRAF(V600E)突变与...