中文摘要：

循环游离DNA以细胞外游离形式存在于血液中,可由正常细胞和癌细胞释放。非小细胞肺癌（NSCLC）患者血液中游离DNA水平高于正常人,且循环游离DNA可以反映癌组织的基因突变,甲基化状态,拷贝数改变,杂合子丢失等特征,是肺癌诊断、治疗、预后检测中具有巨大潜力的生物学指标。本综述简要介绍了循环游离DNA的生物学特性,并对近年来循环游离DNA基因改变检测在NSCLC中的临床应用进行阐述。

英文摘要：

Circulating-cell-free DNA（cf DNA）,Which is released by normal cells or tumor cells,is defined as extracellular DNA in the blood.The cf DNA levels in non-small cell lung cancer（NSCLC）patients are higher than those in healthy controls. cf DNA also carries the features of tumor tissue,such as mutations,methylations,copy number changes,and loss of heterozygosis.cf DNA is apotential biomarker in the diagnosis,management,and prognosis of NSCLC. The biological features of cf DNA,and its clinical utility as a blood biomarker in genomic alterations in NSCLC is reviewed.