Chen Ying-Chieh, Tsao Chun-Ming, Kuo Chih-Chi, Yu Mu-Hsien, Lin Ya-Wen, Yang Chu-Ying, Li Hsin-Jung, Yan Ming-De, Wang Tun-Jun, Chou Yu-Ching, Su Her-Young
Division of Pulmonary and Critical Care, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, ROC; Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei, Taiwan, ROC.
Bureau of Investigation, Ministry of Justice, New Taipei City, Taiwan, ROC.
Taiwan J Obstet Gynecol. 2015 Oct;54(5):572-9. doi: 10.1016/j.tjog.2015.08.010.
Most endometrial carcinomas appear to develop from precursors (e.g., endometrial hyperplasia) that progress for several years. Patients who are ultimately diagnosed with carcinoma often present clinically with complaints of abnormal vaginal bleeding years before diagnosis, which offers an opportunity for early diagnosis and curative treatment. The analysis of DNA methylation may be used as a method for detecting endometrial cancer (EC). To test the potential clinical application of this method, we used quantitative methylation analysis of five genes in a full spectrum of endometrial lesions.
This hospital-based, prospective, case-controlled study was conducted on 68 patients, which included patients who had a normal endometrium (n = 18), hyperplasia of the endometrium (n = 24), and EC (n = 26). Methylation levels of the following genes were determined by using real-time methylation-specific polymerase chain reaction (PCR) amplification: zinc finger protein 177 (ZNF177), collagen type XIV α1 (COL14A1), dihydropyrimidinase-like 4 (DPYSL4), homeobox A9 (HOXA9), transmembrane protein with epidermal growth factor-like and two follistatin-like domains 2 (TMEFF2). The methylation index (MI) cutoff values for the different diagnoses were determined to test the sensitivity and specificity of the method and to generate the receiver operating characteristic (ROC) curves. The Mann-Whitney U test was used to test between-group differences in the MI.
The MI of the five genes was significantly higher in EC than the MIs in specimens of hyperplasia of endometrium and normal appearance (p < 0.001). The ROC analysis demonstrated that the sensitivity, specificity, and accuracy for detecting EC were 92.3%, 94.4%, and 95.1%, respectively, for ZNF177; 92.3%, 94.4%, and 95.7%, respectively, for COL14A1; 80.8%, 94.4%, and 81.4%, respectively, for HOXA9; 65.4%, 94.4%, and 89.5%, respectively, for TMEFF2; and 61.5%, 94.4%, and 63.3%, respectively, for DPYSL4. The combined testing of ZNF177 and COL14A1 had the best specificity (100%), but compromised sensitivity (88.5%).
Promoter methylation of ZNF177, COL14A1, HOXA9, DPYSL4, and TMEFF2 genes is a frequent epigenetic event in EC. Furthermore, the epigenetic hypermethylation of TMEFF2 may be a valuable marker for identifying undetected EC within endometrial hyperplasia.
大多数子宫内膜癌似乎由前驱病变（如子宫内膜增生）发展而来，这个过程会持续数年。最终被诊断为癌症的患者在临床诊断前数年通常会出现异常阴道出血的症状，这为早期诊断和根治性治疗提供了机会。DNA甲基化分析可作为检测子宫内膜癌（EC）的一种方法。为测试该方法的潜在临床应用价值，我们对一系列子宫内膜病变中的五个基因进行了定量甲基化分析。
本研究为基于医院的前瞻性病例对照研究，共纳入68例患者，包括子宫内膜正常的患者（n = 18）、子宫内膜增生患者（n = 24）和子宫内膜癌患者（n = 26）。通过实时甲基化特异性聚合酶链反应（PCR）扩增测定以下基因的甲基化水平：锌指蛋白177（ZNF177）、十四型胶原蛋白α1（COL14A1）、二氢嘧啶酶样4（DPYSL4）、同源盒A9（HOXA9）、具有表皮生长因子样和两个卵泡抑素样结构域的跨膜蛋白2（TMEFF2）。确定不同诊断的甲基化指数（MI）临界值，以测试该方法的敏感性和特异性，并生成受试者工作特征（ROC）曲线。采用曼-惠特尼U检验来检验MI的组间差异。
五个基因的MI在子宫内膜癌中显著高于子宫内膜增生和外观正常标本中的MI（p < 0.001）。ROC分析表明，ZNF177检测子宫内膜癌的敏感性、特异性和准确性分别为92.3%、94.4%和95.1%；COL14A1分别为92.3%、94.4%和95.7%；HOXA9分别为80.8%、94.4%和81.4%；TMEFF2分别为65.4%、94.4%和89.5%；DPYSL4分别为61.5%、94.4%和63.3%。ZNF177和COL14A联合检测具有最佳特异性（100%），但敏感性有所下降（88.5%）。
ZNF177、COL14A1、HOXA9、DPYSL4和TMEFF2基因的启动子甲基化是子宫内膜癌中常见的表观遗传事件。此外，TMEFF2的表观遗传高甲基化可能是识别子宫内膜增生中未被检测到的子宫内膜癌的有价值标志物。
