Deregulation of the epigenome underlies oncogenesis in numerous primary brain tumours in children and young adults. In this review, we describe how recurrent mutations in isocitrate dehydrogenases or histone 3 variants (oncohistones) in gliomas, expression of the oncohistone mimic enhancer of Zeste homologs inhibiting protein (EZHIP) in a subgroup of ependymoma, and epigenetic alterations in other embryonal tumours promote oncogenicity. We review the proposed mechanisms of cellular transformation, current tumorigenesis models and their link to development. We further stress the narrow developmental windows permissive to their oncogenic potential and how this may stem from converging effects deregulating polycomb repressive complex (PRC)2 function and targets. As altered chromatin states may be reversible, improved understanding of aberrant cancer epigenomes could orient the design of effective therapies.

表观基因组的失调是儿童和年轻人许多原发性脑肿瘤的肿瘤发生的基础。在这篇综述中，我们描述了胶质瘤中异柠檬酸脱氢酶或组蛋白 3 变体（癌组蛋白）的反复突变、室管膜瘤亚组中 Zeste 同源抑制蛋白 (EZHIP) 的癌组蛋白模拟增强子的表达以及其他胚胎肿瘤中的表观遗传改变如何促进致癌性。我们回顾了提出的细胞转化机制、当前的肿瘤发生模型及其与发育的联系。我们进一步强调了允许其致癌潜力的狭窄发育窗口，以及这可能源于放松多梳抑制复合物 (PRC)2 功能和靶点的聚合效应。由于改变的染色质状态可能是可逆的，