Powrózek Tomasz, Krawczyk Paweł, Kucharczyk Tomasz, Milanowski Janusz
Department of Pneumonology, Oncology and Allergology, Medical University of Lublin, Jaczewskiego 8, 20-954, Lublin, Poland,
Med Oncol. 2014 Apr;31(4):917. doi: 10.1007/s12032-014-0917-4. Epub 2014 Mar 16.
Currently, there are no sensitive diagnostic tests that could allow early detection of lung cancer. Among some cancer patients, epigenetic changes in the nature of methylation of different gene promoter regions are observed, which affect expression of suppressor genes such as septin 9 (SEPT9). Due to the ability of detecting these changes in free circulating DNA in peripheral blood, such genes may become ideal markers in early and noninvasive diagnostics of cancer. Methylation of SEPT9 promoter region in plasma DNA is observed frequently in colorectal cancer patients. The aim of the study was to define the frequency of SEPT9 promoter methylation in lung cancer patients and evaluation of usefulness of this marker in early diagnostic of lung cancer. Plasma samples were obtained from 70 untreated patients with different lung cancer pathological diagnosis and disease stage and from 100 healthy individuals. DNA was isolated from peripheral blood plasma and was then subjected to bisulfitation, purification and elution using Abbott mSEPT9 Detection Kit. Methylation level was assessed by real-time PCR with the use of specific SEPT9 promoter methylation probe. Each sample was assayed in the presence of positive and negative control. SEPT9 promoter methylation was detected in 31 (44.3% of the whole studied group) of lung cancer patients finding the result positive when methylation was detected in 1 out of 3 repetitions of each test sample determinations. The marker was present in patients with different pathological diagnosis and disease stage. Analysis of SEPT9 promoter region methylation may be useful in early diagnosis of lung cancer.
目前，尚无能够实现肺癌早期检测的敏感诊断测试。在一些癌症患者中，观察到不同基因启动子区域甲基化性质的表观遗传变化，这会影响诸如septin 9（SEPT9）等抑癌基因的表达。由于能够检测外周血中游离循环DNA的这些变化，此类基因可能成为癌症早期和非侵入性诊断的理想标志物。在结直肠癌患者中，经常观察到血浆DNA中SEPT9启动子区域的甲基化。本研究的目的是确定肺癌患者中SEPT9启动子甲基化的频率，并评估该标志物在肺癌早期诊断中的实用性。从70例未经治疗、具有不同肺癌病理诊断和疾病分期的患者以及100名健康个体中获取血浆样本。从外周血血浆中分离DNA，然后使用雅培mSEPT9检测试剂盒进行亚硫酸氢盐处理、纯化和洗脱。使用特异性SEPT9启动子甲基化探针通过实时PCR评估甲基化水平。每个样本均在阳性和阴性对照存在的情况下进行检测。在31例（占整个研究组的44.3%）肺癌患者中检测到SEPT9启动子甲基化，当每个测试样本测定的3次重复中有1次检测到甲基化时，结果为阳性。该标志物存在于具有不同病理诊断和疾病分期的患者中。分析SEPT9启动子区域甲基化可能有助于肺癌的早期诊断。
