BCOR is expressed in a new brain tumour entity, i.e. ‘CNS tumour with BCOR internal tandem duplication’ (HGNET BCOR) but not in several other high grade paediatric brain tumours investigated. Immunohistochemical detection of BCOR expression may therefore serve as a potential diagnostic marker. Nevertheless, in rare paediatric glioma cases recurrent EP300-BCOR fusions were detected, which resulted in strong BCOR immunopositivity. We have therefore examined other, not analysed so far, types of central nervous system (CNS) tumours, pineoblastoma and germinoma, to assess a potential involvement of BCOR in these tumours. Levels of BCOR RNA expression were investigated by NanoString nCounter system analysis in a series of altogether 66 high grade paediatric tumours, including four pineoblastoma cases. Immunohistological detection of BCOR was performed in eight pineoblastoma, five germinoma and four atypical teratoid rhabdoid tumours (ATRTs), all located in the pineal region. We detected BCOR expression in all pineoblastomas, at the RNA and protein levels, but not in germinomas and ATRTs. Further analysis of pineoblastoma samples did not reveal the presence of either BCOR internal tandem duplication or BCOR fusion involvement. Positive immunohistological BCOR nuclear reaction in pineoblastoma may therefore differentiate this type of tumour from other high grade tumours located in the pineal region.

中文翻译：

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BCOR 在儿童松果体母细胞瘤中的表达

BCOR 在一种新的脑肿瘤实体中表达，即“具有 BCOR 内部串联重复的 CNS 肿瘤”(HGNET BCOR)，但在所研究的其他几种高级儿童脑肿瘤中不表达。因此，BCOR 表达的免疫组织化学检测可作为潜在的诊断标记。然而，在罕见的儿童神经胶质瘤病例中，检测到复发的 EP300-BCOR 融合，这导致了强烈的 BCOR 免疫阳性。因此，我们检查了迄今为止尚未分析的其他类型的中枢神经系统 (CNS) 肿瘤、松果体母细胞瘤和生殖细胞瘤，以评估 BCOR 在这些肿瘤中的潜在参与。通过 NanoString nCounter 系统分析，研究了一系列总共 66 个高级儿科肿瘤（包括 4 个松果体母细胞瘤病例）的 BCOR RNA 表达水平。在 8 个松果体母细胞瘤、5 个生殖细胞瘤和 4 个非典型畸胎瘤样横纹肌瘤 (ATRT) 中进行了 BCOR 的免疫组织学检测，这些肿瘤均位于松果体区。我们在所有松果体母细胞瘤中在 RNA 和蛋白质水平上检测到 BCOR 表达，但在生殖细胞瘤和 ATRT 中未检测到。对松果体母细胞瘤样本的进一步分析未发现存在 BCOR 内部串联重复或 BCOR 融合参与。因此，松果体母细胞瘤中的阳性免疫组织学 BCOR 核反应可能将这种类型的肿瘤与位于松果体区的其他高级肿瘤区分开来。