循环核酸是指存在于血液 (血浆或血清 )中的细胞外游离DNA和RNA。本文对血浆 (血清 )DNA如Ras和 p5 3基因突变、微卫星改变、肿瘤抑癌基因启动子的高甲基化、线粒体DNA突变和肿瘤相关病毒DNA等以及肿瘤相关RNA如酪氨酸酶RNA、端粒酶成分RNA、不同肿瘤相关基因编码的mRNA和病毒RNA等检测在肿瘤诊断和预后中的意义进行了综述 ,并简要展望了循环核酸测定的应用前景。 Circulating nucleic acids refer to extracellular free DNA and RNA present in the blood (plasma or serum). In this paper, the plasma (serum) DNA such as Ras and p5 3 gene mutations, microsatellite changes, tumor suppressor gene promoter hypermethylation, mitochondrial DNA mutations and tumor-associated virus DNA and tumor-associated RNA such as tyrosinase RNA The significance of detection of granzyme component RNA, mRNA encoded by different tumor-associated genes and viral RNA in tumor diagnosis and prognosis was reviewed. The application prospect of circulating nucleic acid assay was briefly predicted.