液体活检在结直肠癌诊治中应用价值

The application value of liquid biopsy in the diagnosis and treatment of colorectal cancer

液体活检可基于血液中检出的细胞和基因状态反映全身肿瘤的特点,同时具有无创、全面、实时动态监测等优势。在结直肠外科领域,应用于科研和临床的液体活检包括:循环肿瘤细胞(CTCs)、循环肿瘤DNA(ctDNA)、细胞游离DNA(cfDNA)、循环肿瘤微小RNA(ctmiRNA)、外泌体等。液体活检可用于检测结直肠癌术后肿瘤的微小残留病变,预测结直肠癌术后以及结直肠癌肝转移转化治疗后的复发风险,指导术后辅助治疗,评估放化疗等抗肿瘤治疗的根治度,动态变化反映抗肿瘤疗效并预测耐药机制,指导术后辅助治疗的决策及强度,还可替代肿瘤组织用于基因检测和指导靶向药物应用。目前,随着二代测序技术的成熟,ctDNA/cfDNA在结直肠肿瘤诊治中的应用逐渐增多,越来越受到重视;而CTCs的检出存在较大的个体差异,需要纵向比对治疗前后病人CTCs计数的动态变化才能显示其临床意义;ctmiRNA和外泌体则更多是用于基础研究和临床前的探索。

Liquid biopsy can reflect the characteristics of systemic tumors based on the state of detected cells or genes and possesses advantages including their non-invasive,comprehensive,and real-time dynamic nature.Liquid biopsy markers widely applied to basic research and clinical practice in the field of colorectal cancer include circulating tumor cells(CTCs),circulating tumor DNAs(ctDNAs),cell-free DNA(cfDNA),circulating tumor microRNA(ctmiRNAs)and exosomes.Liquid biopsy could be applied to detect postoperative tumor minimal residual disease(MRD),predict the recurrence risk after operation or chemotherapy for liver metastasis,guide postoperative adjuvant therapy,evaluate the curative effect of anti-tumor treatments such as radiotherapy and chemotherapy,and reflect the dynamic changes;the dynamic changes reflect the efficacy of anti-tumor treatments,forecast the mechanism of drug resistance,guide the decision-making and intensity of postoperative adjuvant therapy,as well as replace tumor tissue in the application of genetic testing and guiding the usage of targeted drugs.With the maturity of next-generation sequencing technology,cfDNA/ctDNA has gradually been applied in the diagnosis and treatment of colorectal cancer,gaining more and more attention.The detection of CTCs varies greatly from individual to individual,and it is necessary to compare the dynamic changes in CTC counts before and after treatment to demonstrate their clinical significance;while ctmiRNAs and exosomes are mainly used for basic research and preclinical exploration.