Department of Clinical Chemistry, Centre for Research and Development of Medical Diagnostic Laboratories, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand.
Mol Med Rep. 2018 Mar;17(3):4145-4153. doi: 10.3892/mmr.2017.8319. Epub 2017 Dec 19.
Cholangiocarcinoma (CCA) is the most common primary liver cancer in Northeastern Thailand where liver fluke infection is highly endemic. Although aberrant DNA methylation in CCA has been reported by several investigators, little is known regarding the associations between them. In the present study, the results obtained from our previously published methylation array were analyzed and 10 candidate genes involved in DNA repair [protein phosphatase 4 catalytic subunit (PPP4C)], apoptosis [runt related transcription factor 3 (RUNX3), interferon regulatory factor 4 (IRF4), ubiquitin C‑terminal hydrolase L1 (UCHL1) and tumor protein p53 inducible protein 3 (TP53I3)], cell proliferation [cyclin D2 (CCND2) and Ras association domain family member 1 (RASSF1)], drug metabolism [aldehyde dehydrogenase 1 family member A3 (ALDH1A3) and solute carrier family 29 member 1 (SLC29A1)] and angiogenesis [human immunodeficiency virus‑1 tat interactive protein 2 (HTATIP2)] were selected for quantification of their methylation levels in 54 CCA and 19 adjacent normal tissues using methylation‑sensitive high‑resolution melting. The associations between the methylation status of the individual genes and clinical parameters were statistically analyzed. High methylation levels were observed in UCHL1, IRF4, CCND2, HTATIP2 and TP53I3. The median methylation level of UCHL1 was 57.3% (range, 3.15 to 88.7%) and HTATIP2 was 13.6% (range, 7.5 to 36.7%). By contrast, low methylation of HTATIP2 and UCHL1 was identified in adjacent normal tissues. The methylation status of HTATIP2 and UCHL1 was associated with patients' overall survival. CCA patients with high methylation of HTATIP2 and low methylation of UCHL1 exhibited longer overall survival. In addition, multivariate Cox regression analysis demonstrated that UCHL1 methylation was an independent factor for CCA with hazard ratio of 1.81 (95% confidence interval, 1.01‑3.25) in high methylation group. The combination of HTATIP2 and UCHL1 methylation status strongly supported their potential predictive biomarker in which patients with CCA who had high methylation of HTATIP2 and low methylation of UCHL1 showed longer overall survival than those with low HTATIP2 methylation and high UCHL1 methylation. In conclusion, the present study revealed the value of aberrant DNA methylation of HTATIP2 and UCHL1, which may serve as a potential predictive biomarker for CCA.
胆管癌（CCA）是泰国东北部最常见的原发性肝癌，那里的肝吸虫感染高度流行。尽管已有几位研究人员报道了 CCA 中的异常 DNA 甲基化，但关于它们之间的关联却知之甚少。在本研究中，我们对之前发表的甲基化芯片的结果进行了分析，并选择了 10 个涉及 DNA 修复的候选基因[蛋白磷酸酶 4 催化亚基（PPP4C）]、凋亡[ runt 相关转录因子 3（RUNX3）、干扰素调节因子 4（IRF4）、泛素 C 端水解酶 L1（UCHL1）和肿瘤蛋白 p53 诱导蛋白 3（TP53I3）]、细胞增殖[周期蛋白 D2（CCND2）和 Ras 相关结构域家族成员 1（RASSF1）]、药物代谢[醛脱氢酶 1 家族成员 A3（ALDH1A3）和溶质载体家族 29 成员 1（SLC29A1）]和血管生成[人类免疫缺陷病毒 1 tat 相互作用蛋白 2（HTATIP2）]，用于使用甲基化敏感高分辨率熔解定量分析 54 例 CCA 和 19 例相邻正常组织中的甲基化水平。统计分析了单个基因的甲基化状态与临床参数之间的关系。UCHL1、IRF4、CCND2、HTATIP2 和 TP53I3 中观察到高甲基化水平。UCHL1 的中位甲基化水平为 57.3%（范围为 3.15%至 88.7%），HTATIP2 为 13.6%（范围为 7.5%至 36.7%）。相比之下，相邻正常组织中 HTATIP2 和 UCHL1 的甲基化水平较低。HTATIP2 和 UCHL1 的甲基化状态与患者的总生存有关。HTATIP2 和 UCHL1 高甲基化和低甲基化的 CCA 患者总生存期较长。此外，多变量 Cox 回归分析表明，UCHL1 甲基化是 CCA 的一个独立因素，高甲基化组的危险比为 1.81（95%置信区间，1.01-3.25）。HTATIP2 和 UCHL1 甲基化状态的组合强烈支持它们作为潜在的预测生物标志物，其中 HTATIP2 高甲基化和 UCHL1 低甲基化的 CCA 患者的总生存期长于 HTATIP2 低甲基化和 UCHL1 高甲基化的患者。总之，本研究揭示了 HTATIP2 和 UCHL1 异常 DNA 甲基化的价值，它们可能成为 CCA 的潜在预测生物标志物。
