Wang Leiming, Li Zhuo, Liu Cuicui, Chen Li, Liu Li, Hu Zeliang, Zhao Lihong, Lu Dehong, Teng Lianghong
Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.
Department of Pathology, Xuanwu Hospital, Capital Medical University, Beijing 100053, China.
Pathol Res Pract. 2017 Dec;213(12):1489-1493. doi: 10.1016/j.prp.2017.10.007. Epub 2017 Oct 10.
MGMT promoter methylation is considered as a prognostic and predictive biomarker indicating response to chemotherapy and radiotherapy in glioblastoma. A number of different methods and platforms including pyrosequencing (PSQ), quantitative methylation-specific PCR (qMSP) and immunohistochemistry (IHC), methylation-sensitive high resolution melting (MS-HRM) and NGS (Next Generation Sequencing) have been used to detect MGMT promoter methylation in gliomas. However, controversy remains about the most appropriate method to use for analyzing MGMT status. The MGMT promoter methylation status of a total of 350 gliomas and gangliogliomas was examined using PSQ, qMSP and IHC in parallel. Using PSQ as a recommended standard method, the sensitivity, specificity, positive/negative predictive value and correlation with the other assays were calculated. Among 350 glioma and ganglioglioma cases, the MGMT promoter tested positive for methylation in 53.1%, 55.4%, and 70.3% of the cases by PSQ, qMSP and IHC, respectively. The sensitivity and specificity of qMSP were 97.8% and 92.7%, respectively. Twelve cases that tested positive for methylation using qMSP were negative according to PSQ, and four cases that were negative according to qMSP tested positive according to PSQ. The concordance rate between PSQ and qMSP was 90.8%. The sensitivity and specificity of IHC for the detection of MGMT at the protein level were 84.4% and 45.7%, respectively. The concordance rate between PSQ and IHC was 30.8%. This study demonstrated that qMSP is an effective and rapid detection method for routine use in pathology laboratories for the identification of MGMT promoter methylation. A combination of IHC and qMSP assays can provide high sensitivity and specificity for the prediction of MGMT status. A few cases that tested negative with PSQ did harbor MGMT promoter methylation, as confirmed by qMSP and sequencing, and this subgroup of patients may benefit from temozolomide.
O6-甲基鸟嘌呤-DNA甲基转移酶（MGMT）启动子甲基化被认为是一种预后和预测生物标志物，可指示胶质母细胞瘤对化疗和放疗的反应。包括焦磷酸测序（PSQ）、定量甲基化特异性PCR（qMSP）和免疫组织化学（IHC）、甲基化敏感高分辨率熔解（MS-HRM）和二代测序（NGS）在内的许多不同方法和平台已被用于检测胶质瘤中的MGMT启动子甲基化。然而，关于用于分析MGMT状态的最合适方法仍存在争议。我们同时使用PSQ、qMSP和IHC检测了总共350例胶质瘤和神经节胶质瘤的MGMT启动子甲基化状态。以PSQ作为推荐的标准方法，计算了敏感性、特异性、阳性/阴性预测值以及与其他检测方法的相关性。在350例胶质瘤和神经节胶质瘤病例中，通过PSQ、qMSP和IHC检测，MGMT启动子甲基化检测阳性的病例分别占53.1%、55.4%和70.3%。qMSP的敏感性和特异性分别为97.8%和92.7%。12例假阳性的病例，qMSP检测甲基化呈阳性，但PSQ检测呈阴性；4例假阴性的病例，qMSP检测甲基化呈阴性，但PSQ检测呈阳性。PSQ与qMSP之间的一致性率为90.8%。免疫组织化学在蛋白质水平检测MGMT的敏感性和特异性分别为84.4%和45.7%。PSQ与IHC之间的一致性率为30.8%。本研究表明，qMSP是病理实验室常规用于鉴定MGMT启动子甲基化的一种有效且快速的检测方法。免疫组织化学和qMSP检测相结合可为MGMT状态的预测提供高敏感性和特异性。少数PSQ检测呈阴性的病例，经qMSP和测序证实确实存在MGMT启动子甲基化，这部分患者可能从替莫唑胺治疗中获益。
