ABSTRACT

Introduction: Cell-free DNA (cfDNA) circulates in the blood for a long time. The levels of cfDNA in the blood are assayed in cancer diagnostics because they are closely related to the tumor burden of patients.

Areas covered: cfDNA escapes the action of DNA-hydrolyzing enzymes, being a part of supramolecular complexes or interacting with the plasma membrane of blood cells. cfDNA has heterogeneous size and composition, which impose various restrictions on both isolation methods and subsequent analysis. cfDNA concentration and structural changes with the development of diseases highlight the high potential of cfDNA as a diagnostic and prognostic marker. The concentration of cfDNA released in the blood by tumor cells determines the specificity of such diagnostics and the required blood volume. The present review aimed to synthesize the available data on cfDNA concentration in the cancer patient’s blood as well as pre-analytical, analytical, and biological factors, which interfere with cfDNA concentration.

Expert opinion: The concentration of cfDNA and tumor cell DNA (ctDNA), and the over-presentation of DNA loci in cfDNA must be considered when looking for tumor markers. Some inconsistent data on cfDNA concentrations (like those obtained by different methods) suggest that the study of cfDNA should be continued.

摘要

简介: 游离 DNA (cfDNA) 在血液中循环很长时间。血液中 cfDNA 的水平用于癌症诊断，因为它们与患者的肿瘤负担密切相关。

涵盖的领域：cfDNA 逃避 DNA 水解酶的作用，成为超分子复合物的一部分或与血细胞的质膜相互作用。cfDNA 具有异质的大小和组成，这对分离方法和后续分析都施加了各种限制。随着疾病的发展，cfDNA 浓度和结构变化突出了 cfDNA 作为诊断和预后标志物的巨大潜力。肿瘤细胞在血液中释放的 cfDNA 浓度决定了这种诊断方法的特异性和所需的血容量。本综述旨在综合有关癌症患者血液中 cfDNA 浓度以及干扰 cfDNA 浓度的分析前、分析和生物学因素的可用数据。

专家意见：在寻找肿瘤标志物时，必须考虑cfDNA和肿瘤细胞DNA（ctDNA）的浓度，以及cfDNA中DNA位点的过度呈现。一些关于 cfDNA 浓度的不一致数据（如通过不同方法获得的数据）表明应继续对 cfDNA 的研究。