Vascular endothelial growth factor (VEGF) has a crucial role in the angiogenesis of various tumors, including glioma. As the levels of VEGF would change in patients with glioma, we conducted the current systematic review and meta-analysis to more clearly determine the VEGF level alterations in different grades of glioma. PubMed and Scopus databases were sensitively searched for all the possible keywords addressing glioma and VEGF. Case–control and cohort studies on human subjects, which measured VEGF levels were eligible to be included in the study. Out of a total number of 3,612 studies, 22 studies were included and 12 studies entered the meta-analysis. This review revealed that serum levels of VEGF in glioma patients were 1.56 pg/dL higher compared to healthy controls ( P = 0.05). Besides, immunohistochemistry (IHC) measurement of VEGF in surgical biopsies indicated significant difference in these two groups as well ( P = 0.02). Yet, there was not a significant difference between patients with low-grade gliomas (World Health Organization (WHO) grades I-II, LGG) and those with high-grade gliomas (WHO grades III-IV, HGG) ( P = 0.43). The results of this systematic review and meta-analysis demonstrate that VEGF levels would significantly increase in glioma, and therefore, could be potentially considered as a biomarker for this cancer.

中文翻译：

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胶质瘤患者的 VEGF 水平：系统评价和荟萃分析

血管内皮生长因子 (VEGF) 在包括神经胶质瘤在内的各种肿瘤的血管生成中起着至关重要的作用。由于胶质瘤患者的VEGF水平会发生变化，我们进行了当前的系统回顾和荟萃分析，以更清楚地确定不同级别胶质瘤的VEGF水平变化。敏感地搜索 PubMed 和 Scopus 数据库中所有可能涉及神经胶质瘤和 VEGF 的关键词。对人类受试者进行的病例对照和队列研究，测量了 VEGF 水平，符合纳入研究的条件。在总共 3,612 项研究中，22 项研究被纳入，12 项研究进入荟萃分析。该综述显示，与健康对照相比，胶质瘤患者的血清 VEGF 水平高 1.56 pg/dL（ P = 0.05）。除了，手术活检中 VEGF 的免疫组织化学 (IHC) 测量表明这两组之间也存在显着差异（ P = 0.02）。然而，低级别胶质瘤患者（世界卫生组织（WHO）I-II级，LGG）和高级别胶质瘤患者（WHO III-IV级，HGG）之间没有显着差异（ P = 0.43） . 该系统评价和荟萃分析的结果表明，神经胶质瘤中 VEGF 水平会显着增加，因此可能被视为这种癌症的生物标志物。