循环肿瘤DNA及其在癌症液体活检中的应用

Circulating tumor DNA and its application in liquid biopsy of cancer

目前对癌症组织进行基因分型仍旧是癌症临床诊断和治疗的黄金依据.然而癌症组织往往很难获取,并且无法体现癌症组织的异质性和组织各个部位基因突变的情况,因此出现了许多肿瘤治疗方式,甚至包括分子靶向药的失效.非侵入性的血液液体活检为解决癌症异质性检测带来了新的机遇.血液中的循环肿瘤DNA(ct DNA)作为生物标记具有对整个肿瘤组织进行基因分型的潜力.本综述主要阐述ct DNA的如下几个方面:ct DNA的生物学特性;肿瘤特异性ct DNA突变;ct DNA的表观遗传学改变;ct DNA的检验方法;ct DNA在肿瘤诊断、治疗和预后中的潜在应用.

Tissue biopsy and genotyping are standard diagnostic procedures for categorizing tumors for clinical decisions at present. However, tumor tissues are often difficult to obtain and only provide a snapshot. Tumor heterogeneity is a significant cause of failures of cancer therapeutics, even molecularly targeted thera- pies. Noninvasive liquid biopsy from blood has been attempted to characterize tumor heterogeneity. Cell-free circulating tumor DNA （ctDNA） in the bloodstream is a versatile biomarker with good potential to genotype the entire tumor. This review focuses on the following aspects of ctDNA： the biology of ctDNA; tumor-specific ctDNA mutations; the epigenetic alterations of ctDNA; ctDNA detection methods; the potential application of ctDNA in the diag- nosis, treatment and prognosis of tumor.