Cao Siting, Yu Shuang, Yin Yali, Su Lei, Hong Shubin, Gong Yingying, Lv Weiming, Li Yanbing, Xiao Haipeng
Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
Department of Endocrinology, Peking University Shenzhen Hospital, Shenzhen, China.
Ann Transl Med. 2020 Oct;8(19):1225. doi: 10.21037/atm-20-4544.
Circulating cell-free DNA (cfDNA) serves as a biomarker in multiple malignant diseases. However, controversy still surrounds the role of cfDNA detection in the diagnosis and monitoring of papillary thyroid carcinoma (PTC). This study set out to identify the role of cfDNA detection in distinguishing between benign and malignant thyroid nodules.
Tissue, blood cell, and plasma samples were collected from 10 patients with benign nodules and 10 patients with malignant nodules. The DNA isolated from these samples was subject to PCR-based amplification using primers designed for 50 proto-oncogenes and tumor suppressor genes. PCR products were sequenced using Illumina technology, and the mutations were detected with varScan among sequencing data for each sample and comparative analysis was carried out.
Through amplicon sequencing, we found one non-synonymous somatic mutation in the benign nodules and three in the malignant nodules. Among these four mutations, BRAF mutation was detected in the tissue samples of 8 out of the 10 PTC patients, but it was not detected in the benign nodules. However, no BRAF mutation was detected in cfDNA. Further differential analysis of cfDNA indicated that some genes had more mutations in benign patients than in malignant patients, such as MET and IDH, and some genes had more mutations in malignant patients, such as PIK3CA and EZH2.
We found that BRAF mutation was a credible disease-related mutation in PTC; however, it could not be detected in cfDNA. Moreover, there was a large difference in mutation gene distribution between benign and malignant thyroid nodules.
循环游离DNA（cfDNA）在多种恶性疾病中作为生物标志物。然而，cfDNA检测在甲状腺乳头状癌（PTC）诊断和监测中的作用仍存在争议。本研究旨在确定cfDNA检测在鉴别甲状腺良恶性结节中的作用。
收集10例良性结节患者和10例恶性结节患者的组织、血细胞和血浆样本。从这些样本中分离的DNA使用针对50个原癌基因和抑癌基因设计的引物进行基于PCR的扩增。PCR产物使用Illumina技术进行测序，在每个样本的测序数据中用varScan检测突变并进行比较分析。
通过扩增子测序，我们在良性结节中发现1个非同义体细胞突变，在恶性结节中发现3个。在这4个突变中，10例PTC患者中有八例的组织样本中检测到BRAF突变，但在良性结节中未检测到。然而，在cfDNA中未检测到BRAF突变。cfDNA的进一步差异分析表明，一些基因在良性患者中的突变比恶性患者更多，如MET和IDH，而一些基因在恶性患者中的突变更多，如PIK3CA和EZH2。
我们发现BRAF突变是PTC中一个可靠的疾病相关突变；然而，在cfDNA中无法检测到。此外，甲状腺良恶性结节之间的突变基因分布存在很大差异。
