Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Department of Chemical Pathology, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong SAR, China.
Science. 2021 Apr 9;372(6538). doi: 10.1126/science.aaw3616.
Liquid biopsies that analyze cell-free DNA in blood plasma are used for noninvasive prenatal testing, oncology, and monitoring of organ transplant recipients. DNA molecules are released into the plasma from various bodily tissues. Physical and molecular features of cell-free DNA fragments and their distribution over the genome bear information about their tissues of origin. Moreover, patterns of DNA methylation of these molecules reflect those of their tissue sources. The nucleosomal organization and nuclease content of the tissue of origin affect the fragmentation profile of plasma DNA molecules, such as fragment size and end motifs. Besides double-stranded linear fragments, other topological forms of cell-free DNA also exist-namely circular and single-stranded molecules. Enhanced by these features, liquid biopsies hold promise for the noninvasive detection of tissue-specific pathologies with a range of clinical applications.
液体活检通过分析血液血浆中的游离 DNA 进行，可用于非侵入性产前检测、肿瘤学以及器官移植受者的监测。游离 DNA 分子从各种身体组织释放到血浆中。游离 DNA 片段的物理和分子特征及其在基因组上的分布携带有关其组织来源的信息。此外，这些分子的 DNA 甲基化模式反映了其组织来源的模式。组织中原核小体的组成和核酶含量会影响血浆 DNA 分子的片段化谱，例如片段大小和末端基序。除了双链线性片段外，游离 DNA 还存在其他拓扑形式，即环状和单链分子。这些特征增强了液体活检的潜力，可用于非侵入性检测具有广泛临床应用的组织特异性病理。
