Meningiomas are highly vascularized tumors originating from arachnoid cap cells of the leptomeninges. The majority of meningiomas are classified as World Health Organization (WHO) grade I and display a benign clinical course with a low risk of recurrence. In contrast, WHO grade III meningiomas carry a high risk of recurrence and poor prognosis. However, it is commonly recognized that histopathologic grading does not always reliably predict recurrence or progression of meningiomas. Fatty acid-binding protein 4 (FABP4) is a small molecular weight lipid chaperone that plays a proangiogenic role in vascular endothelial cells. FABP4 is not expressed in normal brain vasculature but is detected in some glioblastoma and arteriovenous malformations. The expression pattern of FABP4 in meningiomas have not been reported to date. We analyzed FABP4 expression in a cohort of paraffin-embedded meningioma specimens by immunohistochemistry and double immunofluorescence analyses. FABP4 expression was detected in a subset of endothelial cells in 47 of 48 meningioma samples analyzed. Interestingly, tumor cell-FABP4 expression was also detected in only 1 of 22 grade I, none of grade II, but 10 of 12 grade III meningiomas (P<0.0001). These results demonstrate that FABP4 is commonly expressed in meningioma vascular endothelial cells while tumor cell expression of FABP4 is primarily observed in anaplastic meningiomas. A combination of FABP4 immunostaining with histopathologic grading might provide a more accurate prediction of the biological behavior of meningiomas than histopathologic grading alone.

中文翻译：

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脂肪酸结合蛋白 4 在肿瘤细胞中的表达作为间变性脑膜瘤的潜在标志物

脑膜瘤是高度血管化的肿瘤，起源于软脑膜的蛛网膜帽细胞。大多数脑膜瘤被归类为世界卫生组织 (WHO) I 级，并且表现出良性临床病程，复发风险低。相比之下，WHO III 级脑膜瘤具有高复发风险和不良预后。然而，人们普遍认为，组织病理学分级并不总是可靠地预测脑膜瘤的复发或进展。脂肪酸结合蛋白 4 (FABP4) 是一种小分子量的脂质伴侣，在血管内皮细胞中起促血管生成作用。FABP4 在正常脑血管系统中不表达，但在一些胶质母细胞瘤和动静脉畸形中检测到。FABP4 在脑膜瘤中的表达模式迄今尚未见报道。我们通过免疫组织化学和双重免疫荧光分析分析了一组石蜡包埋的脑膜瘤标本中的 FABP4 表达。在分析的 48 个脑膜瘤样本中的 47 个内皮细胞亚群中检测到 FABP4 表达。有趣的是，肿瘤细胞-FABP4 表达也仅在 22 个 I 级脑膜瘤中的 1 个中检测到，在 II 级中没有检测到，但在 12 个 III 级脑膜瘤中的 10 个中也检测到（P<0.0001）。这些结果表明 FABP4 通常在脑膜瘤血管内皮细胞中表达，而 FABP4 的肿瘤细胞表达主要在间变性脑膜瘤中观察到。FABP4 免疫染色与组织病理学分级的组合可能比单独的组织病理学分级更准确地预测脑膜瘤的生物学行为。