Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada.
PLoS One. 2013 Aug 7;8(8):e68439. doi: 10.1371/journal.pone.0068439. eCollection 2013.
Poor prognosis of hepatocellular carcinoma (HCC) associated with late diagnosis necessitates the development of early diagnostic biomarkers. We have previously delineated the landscape of DNA methylation in HCC patients unraveling the importance of promoter hypomethylation in activation of cancer- and metastasis-driving genes. The purpose of the present study was to test the feasibility that genes that are hypomethylated in HCC could serve as candidate diagnostic markers. We use high resolution melting analysis (HRM) as a simple translatable PCR-based method to define methylation states in clinical samples. We tested seven regions selected from the shortlist of genes hypomethylated in HCC and showed that HRM analysis of several of them distinguishes methylation states in liver cancer specimens from normal adjacent liver and chronic hepatitis in the Shanghai area. Such regions were identified within promoters of neuronal membrane glycoprotein M6-B (GPM6B) and melanoma antigen family A12 (MAGEA12) genes. Differences in HRM in the immunoglobulin superfamily Fc receptor (FCRL1) separated invasive tumors from less invasive HCC. The identified biomarkers differentiated HCC from chronic hepatitis in another set of samples from Dhaka. Although the main thrust in DNA methylation diagnostics in cancer is on hypermethylated genes, our study for the first time illustrates the potential use of hypomethylated genes as markers for solid tumors. After further validation in a larger cohort, the identified DNA hypomethylated regions can become important candidate biomarkers for liver cancer diagnosis and prognosis, especially in populations with high risk for HCC development.
肝细胞癌（HCC）预后不良，诊断较晚，因此需要开发早期诊断生物标志物。我们之前已经描绘了 HCC 患者的 DNA 甲基化图谱，揭示了启动子低甲基化在激活癌症和转移驱动基因中的重要性。本研究的目的是验证 HCC 中低甲基化的基因是否可以作为候选诊断标志物。我们使用高分辨率熔解分析（HRM）作为一种简单的可翻译的基于 PCR 的方法来定义临床样本中的甲基化状态。我们测试了从 HCC 中低甲基化基因短名单中选择的七个区域，结果表明，这些区域中的几个 HRM 分析可以区分上海地区肝癌标本与正常相邻肝和慢性肝炎的甲基化状态。这些区域位于神经元膜糖蛋白 M6-B（GPM6B）和黑色素瘤抗原家族 A12（MAGEA12）基因的启动子中。免疫球蛋白超家族 Fc 受体（FCRL1）中的 HRM 差异将侵袭性肿瘤与侵袭性较低的 HCC 区分开来。在来自达卡的另一组样本中，鉴定出的生物标志物将 HCC 与慢性肝炎区分开来。虽然癌症中 DNA 甲基化诊断的主要重点是在高甲基化基因上，但我们的研究首次说明了低甲基化基因作为实体肿瘤标志物的潜力。在更大的队列中进一步验证后，鉴定出的 DNA 低甲基化区域可成为肝癌诊断和预后的重要候选生物标志物，特别是在 HCC 发病风险较高的人群中。
