Epigenetic dysregulation is a hallmark of many human malignancies, with DNA methylation being a primary mechanism influencing gene expression and maintaining genomic stability. Genome-wide hypomethylation, characteristic of many cancers, is partly attributed to the demethylation of repetitive elements, including LINE-1, a prevalent non-LTR retrotransposon. The methylation status of LINE-1 is closely associated with overall genomic methylation levels in tumors. cfDNA comprises extracellular DNA fragments found in bodily fluids such as plasma, serum, and urine, offering a dynamic snapshot of the genetic and epigenetic landscape of tumors. This real-time sampling provides a minimally invasive avenue for cancer diagnostics, prognostics, and monitoring. The methylation status of LINE-1 in cfDNA has emerged as a promising biomarker, with several studies highlighting its potential in diagnosing and predicting outcomes in cancer patients. Recent research also suggests that cfDNA-based LINE-1 methylation analysis could serve as a valuable tool in evaluating the efficacy of cancer therapies, including immunotherapy. The growing clinical significance of cfDNA calls for a closer examination of its components, particularly repetitive elements like LINE-1. Despite their importance, the role of LINE-1 elements in cfDNA has not been thoroughly gauged. We aim to address this gap by reviewing the current literature on LINE-1 cfDNA assays, focusing on their potential applications in diagnostics and disease monitoring.
表观遗传失调是多种人类恶性肿瘤的标志，其中DNA甲基化是影响基因表达和维持基因组稳定性的主要机制。全基因组低甲基化作为许多癌症的特征，部分归因于重复元件的去甲基化，包括LINE-1这一普遍存在的非长末端重复逆转录转座子。LINE-1的甲基化状态与肿瘤整体基因组甲基化水平密切相关。循环游离DNA（cfDNA）存在于血浆、血清和尿液等体液中，由细胞外DNA片段组成，能够动态反映肿瘤的遗传和表观遗传特征。这种实时采样为癌症诊断、预后评估和治疗监测提供了微创途径。cfDNA中LINE-1的甲基化状态已成为一种有前景的生物标志物，多项研究强调了其在癌症患者诊断和预后预测中的潜力。最新研究还表明，基于cfDNA的LINE-1甲基化分析可作为评估癌症治疗效果（包括免疫疗法）的重要工具。随着cfDNA临床意义的日益凸显，需要对其组成成分（特别是LINE-1等重复元件）进行更深入的研究。尽管这些元件至关重要，但LINE-1在cfDNA中的作用尚未得到充分评估。本文旨在通过综述当前关于LINE-1 cfDNA检测的文献，重点关注其在诊断和疾病监测中的潜在应用，以填补这一研究空白。
LINE-1 cfDNA Methylation as an Emerging Biomarker in Solid Cancers
肿瘤(癌症)患者之家