Institute of Neuropathology, University of Bonn Medical Center, Bonn, Germany.
Neuropathol Appl Neurobiol. 2011 Jun;37(4):406-13. doi: 10.1111/j.1365-2990.2010.01151.x.
The primitive neuroectodermal tumours of central nervous system (CNS-PNET) are a heterogeneous group of neoplasms, occurring in the CNS and composed of undifferentiated or poorly differentiated neuroepithelial cells which may display divergent differentiation along neuronal, astrocytic and ependymal lines. The WHO classification includes in this group of tumours also ependymoblastomas and medulloepitheliomas. Several groups have reported examples of CNS-PNET with combined histological features of ependymoblastoma and neuroblastoma, defined as 'embryonal tumour with abundant neuropil and true rosettes'. The presence of the amplification of chromosome region 19q13.42, common in both ependymoblastoma and embryonal tumour with abundant neuropil and true rosettes, suggests that they represent a histological spectrum of a single biological entity.
We examined 24 cases of ependymoblastoma/embryonal tumour with abundant neuropil and true rosettes (EPBL/ETANTR) for the presence of mutations of TP53 and β-Catenin and for amplification of c-myc/N-myc.
The single strand conformation polymorphism-mutational screening did not identify any mutation in exons 5 to 8 of the TP53 gene. However, we found a point mutation affecting codon 34 (GGA → GTA) of β-Catenin gene resulting in a Glycine → Valine substitution. No cases presented c-myc/N-myc amplification.
EPBL/ETANTRs show molecular features different from other CNS-PNET and medulloblastomas. The presence of alterations in the β-Catenin/WNT pathway seems to be noteworthy due to the close relationship between this pathway and miR-520g encoded in chromosome 19q13.42 region amplified in these tumours.
中枢神经系统原始神经外胚层肿瘤（CNS-PNET）是一组异质性肿瘤，发生在中枢神经系统，由未分化或分化不良的神经上皮细胞组成，这些细胞可能沿着神经元、星形胶质细胞和室管膜细胞的方向分化。世界卫生组织（WHO）分类将神经母细胞瘤和髓上皮瘤也归入这组肿瘤。一些研究小组报告了 CNS-PNET 与神经母细胞瘤的组织学特征相结合的病例，这些肿瘤被定义为“富含神经毡和真性玫瑰花结的胚胎性肿瘤”。染色体 19q13.42 区域扩增的存在，在神经母细胞瘤和富含神经毡和真性玫瑰花结的胚胎性肿瘤中均很常见，这表明它们代表了单一生物学实体的组织学谱。
我们检测了 24 例神经母细胞瘤/富含神经毡和真性玫瑰花结的胚胎性肿瘤（EPBL/ETANTR），以检测 TP53 和 β-Catenin 基因突变以及 c-myc/N-myc 扩增情况。
单链构象多态性-突变筛选未发现 TP53 基因外显子 5 到 8 中的任何突变。然而，我们发现了一个影响 β-Catenin 基因密码子 34（GGA→GTA）的点突变，导致甘氨酸→缬氨酸取代。没有病例出现 c-myc/N-myc 扩增。
EPBL/ETANTRs 表现出与其他 CNS-PNET 和髓母细胞瘤不同的分子特征。β-Catenin/WNT 通路的改变似乎值得注意，因为该通路与这些肿瘤中 19q13.42 区域扩增的 miR-520g 密切相关。
