Nunes Sandra P, Diniz Francisca, Moreira-Barbosa Catarina, Constâncio Vera, Silva Ana Victor, Oliveira Júlio, Soares Marta, Paulino Sofia, Cunha Ana Luísa, Rodrigues Jéssica, Antunes Luís, Henrique Rui, Jerónimo Carmen
Cancer Biology & Epigenetics Group - Research Center, Portuguese Oncology Institute of Porto (CI-IPOP), 4200-072 Porto, Portugal.
Lung Cancer Clinic and Department of Medical Oncology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
J Clin Med. 2019 Sep 19;8(9):1500. doi: 10.3390/jcm8091500.
Lung cancer (LCa) is the most frequently diagnosed and lethal cancer worldwide. Histopathological subtyping, which has important therapeutic and prognostic implications, requires material collection through invasive procedures, which might be insufficient to enable definitive diagnosis. Aberrant DNA methylation is an early event in carcinogenesis, detectable in circulating cell-free DNA (ccfDNA). Herein, we aimed to assess methylation of selected genes in ccfDNA from LCa patients and determine its accuracy for tumor subtyping.
Methylation levels of , , and were assessed in three independent study groups (study group #1: 152 tissue samples; study group #2: 129 plasma samples; study group #3: 28 benign lesions of lung) using quantitative methylation-specific PCR. Associations between gene promoter methylation levels and LCa subtypes were evaluated using non-parametric tests. Receiver operating characteristic (ROC) curve analysis was performed.
In study group #2, and displayed higher methylation levels in small-cell lung cancer (SCLC) than in non-small-cell lung cancer (NSCLC). displayed high sensitivity (63.8%), whereas disclosed high specificity (96.2%) for SCLC detection in ccfDNA. Furthermore, methylation levels showed to be higher in squamous cell carcinoma in comparison with adenocarcinoma in study group #1.
Methylation level assessments in ccfDNA may provide a minimally invasive procedure for LCa subtyping, complementing standard diagnostic procedures.
肺癌（LCa）是全球诊断率和致死率最高的癌症。组织病理学亚型分类对治疗和预后具有重要意义，但需要通过侵入性操作收集材料，这可能不足以进行明确诊断。异常DNA甲基化是致癌过程中的早期事件，可在循环游离DNA（ccfDNA）中检测到。在此，我们旨在评估肺癌患者ccfDNA中选定基因的甲基化情况，并确定其对肿瘤亚型分类的准确性。
使用定量甲基化特异性PCR在三个独立研究组中评估 、 、 和 的甲基化水平（研究组1：152个组织样本；研究组2：129份血浆样本；研究组3：28个肺部良性病变）。使用非参数检验评估基因启动子甲基化水平与肺癌亚型之间的关联。进行了受试者工作特征（ROC）曲线分析。
在研究组2中，与非小细胞肺癌（NSCLC）相比，小细胞肺癌（SCLC）中 和 的甲基化水平更高。 在ccfDNA中检测SCLC时显示出高灵敏度（63.8%），而 显示出高特异性（96.2%）。此外，在研究组1中，鳞状细胞癌的 甲基化水平高于腺癌。
ccfDNA中的甲基化水平评估可为肺癌亚型分类提供一种微创方法，作为标准诊断程序的补充。
