循环肿瘤DNA(circulating tumor DNA,ctDNA)是由肿瘤细胞释放到循环系统中的基因组小片段，其来源于机体所有荷瘤部位，具有含量极低、个体间差异大、半衰期短、匀质性、携带有肿瘤特异性遗传学/表观遗传学变异等特点，与肿瘤的发展进化、休眠耐药、转移复发等密切相关，正逐渐成为肿瘤学分子研究领域的热点。目前针对ctDNA的检测方法和平台种类繁多，主要分为基于PCR和二代测序（next-generation sequence，NGS）的方法，二者各有利弊，需要根据研究目的灵活选择并建立统一标准。随着相关技术的发展和法规的不断完善，ctDNA可作为癌症筛查、早期诊断、个体化治疗及预后评估理想的血源性生物标志物，在肿瘤的精准医疗中必将大放异彩。

Circulating tumor DNAs (ctDNAs) are small genomic fragments released by tumor cells into circulatory system, which come from all of tumor bearing parts of the patients, have characters of extremely low content, great difference among the patients, a short half-time, homogeneous and carrying tumor-specific genetics and epigenetic mutations, and so on, are closely related to development, evolution, dormancy, drug resistance, metastasis and recurrence of the tumor and are gradually becoming key approach in molecular research field of oncology. At present, there is a wide variety of detection methods and platforms for ctDNA, which are mainly divided into PCR-based assay and next-generation sequencing (NGS) , each of both them has their own advantages and disadvantages, and need to be flexibly selected according to research objective, and uniform standards should be established. ctDNA could become as an ideal hematogenous biomarker for tumor screening, early diagnosis, individually therapy and prognostic assessment with development of related techniques and continuous improvement of laws and regulations. This paper reviewed research progresses of ctDNA in the field of oncology.

国家国际科技合作专项资助项目（No. 2014DFA33010）；上海申康医院发展中心市级医院临床辅助科室能力建设项目（No. SHDC22014011）