Wakabayashi Toshihiko, Natsume Atsushi, Hatano Hisashi, Fujii Masazumi, Shimato Shinji, Ito Motokazu, Ohno Masasuke, Ito Satoshi, Ogura Masatoshi, Yoshida Jun
Center for Genetic and Regenerative Medicine, Nagoya University Hospital, Nagoya, Japan.
Neurosurgery. 2009 Mar;64(3):455-61; discussion 461-2. doi: 10.1227/01.NEU.0000340683.19920.E3.
Deoxyribonucleic acid (DNA) methylation of tumor origin can be detected in the serum/plasma of cancer patients. The aim of this study was to detect aberrant p16 promoter methylation as a potential diagnostic marker in the serum of patients with diffuse glioma to differentiate between gliomas and, particularly, to differentiate those in the brainstem from others; this was done by using the modified methylation-specific polymerase chain reaction technique.
The methylation-specific polymerase chain reaction was used to detect p16 methylation in the DNA extracted from 20 astrocytic tumors and 20 oligodendroglial tumors and the corresponding serum samples. Serum samples from 10 healthy individuals were used as controls. The association of p16 hypermethylation in the serum DNA of glioma patients with clinicopathological characteristics was analyzed. In addition, the serum DNA in 7 patients with a brainstem tumor (4 gliomas, 1 schwannoma, 1 cavernous angioma, and 1 ependymoma) was analyzed.
We found p16 methylation in 12 (60%) of the 20 tissues with astrocytoma, but in only 1 of the tissues with oligodendroglioma. Similar methylations were detected in the serum of 9 (75%) of the 12 patients with aberrant methylation in the tumor tissues. No methylated p16 sequences were detected in the peripheral serum of the patients having tumors without these methylation changes or in the 10 healthy controls. Additionally, p16 promoter methylation in the serum was observed in all brainstem astrocytoma cases, but not in other cases.
This assay has potential for use as a serum-based molecular diagnosis technique for diffuse glioma.
癌症患者血清/血浆中可检测到肿瘤来源的脱氧核糖核酸（DNA）甲基化。本研究旨在检测弥漫性胶质瘤患者血清中异常的p16启动子甲基化，作为一种潜在的诊断标志物，以区分胶质瘤，特别是区分脑干胶质瘤与其他胶质瘤；采用改良的甲基化特异性聚合酶链反应技术进行检测。
采用甲基化特异性聚合酶链反应检测20例星形细胞瘤、20例少突胶质细胞瘤及相应血清样本中提取的DNA的p16甲基化。10名健康个体的血清样本用作对照。分析胶质瘤患者血清DNA中p16高甲基化与临床病理特征的相关性。此外，还分析了7例脑干肿瘤患者（4例胶质瘤、1例神经鞘瘤、1例海绵状血管瘤和1例室管膜瘤）的血清DNA。
我们发现20例星形细胞瘤组织中有12例（60%）存在p16甲基化，但少突胶质细胞瘤组织中只有1例存在。在肿瘤组织中存在异常甲基化的12例患者中的9例（75%）血清中检测到类似的甲基化。在无这些甲基化变化的肿瘤患者外周血清或10名健康对照中未检测到甲基化的p16序列。此外，在所有脑干星形细胞瘤病例中均观察到血清中p16启动子甲基化，而其他病例中未观察到。
该检测方法有潜力作为弥漫性胶质瘤基于血清的分子诊断技术。
