液体活检-通向精准医疗的桥梁

组织活检是癌症的标准诊断程序,然而,由于肿瘤异质性和进化,基于组织活检的癌症诊断在癌症发展、预后的评估中具有局限性.液体活检是检测患者体液中含原发肿瘤生物特性分子的技术,包括循环肿瘤细胞、循环肿瘤DNA和外泌体等的检测.液体活检被广泛的应用于辅助诊断、疗效评价、预测预后、监测复发转移、辅助靶向治疗等方面.本文将对液体活检的生物特性及临床应用进展进行综述.     

2023年度液体活检标志物研究进展年终盘点

液体活检技术作为新兴的检测技术,可以非侵入性地反映体内肿瘤的状态,在肿瘤筛检中具有广阔的应用前景。液体活检来源涵盖了不同类型的肿瘤相关物质,包括循环肿瘤DNA、循环肿瘤细胞、细胞外囊泡、非编码RNA等。本文就2023年度液体活检标志物检测及其在肿瘤的早期诊断、疗效评估、预后和复发转移监测等方面的研究新进展进行盘点,为深入探索以液体活检标志物为核心的肿瘤个体化诊治策略提供依据。     

液体活检在结直肠癌领域的研究及应用现状

近年来,液体活检作为新兴的分子诊断技术,具有实时性和可重复性,在临床工作中发挥越来越重要的作用。液体活检主要通过无创方法收集患者体液,检测分析循环肿瘤细胞、循环肿瘤DNA、外泌体等生物学标志物。本文将从液体活检的生物学基础及其在结直肠癌临床应用方面进行综述。     

液体活检在食管鳞状细胞癌中的应用及展望

食管癌是世界上最常见的恶性肿瘤之一,常见的病理类型包括鳞状细胞癌和腺癌,其中鳞状细胞癌占食管癌的90％.食管鳞状细胞癌(ESCC)发病率高,早期诊断困难,复发率高,预后欠佳,目前仍缺乏有效的检测方法.液体活检作为一种新兴技术,包括对循环肿瘤细胞(CTC)、循环肿瘤DNA(ctDNA)、循环肿瘤RNA(ctRNA)、肿瘤来源的外泌体、肿瘤相关血小板(TEP)及循环肿瘤相关微粒等进行检测,可在各类肿瘤的早期诊断、治疗及预后判断中发挥重要作用.本文围绕液体活检技术在ESCC中的最新研究进展作一综述,旨在探讨循环肿瘤标志物在ESCC诊断、治疗及预后判断中的作用及局限性.     

液体活检及其在非小细胞肺癌诊治中的研究进展

随着近几年科学技术的进步,液体活检技术也有了长足的发展,并在肿瘤的早期诊断及后期治疗中扮演着越来越重要的角色。相比于传统的组织活检,液体活检以其独有的无创性、便捷性、高重复性等特点在临床上得到更多的青睐,在未来有着巨大的发展潜力。本文重点探讨了循环肿瘤细胞（circulating tumor cells, CTCs）和循环肿瘤DNA（circulating tumor DNA, ctDNA）,作为液体活检最重要的两个检测对象,其历史、生物学特性,检测手段,局限性及其在非小细胞肺癌诊治中的应用。     

液体活检在神经胶质母细胞瘤诊断中的应用进展

胶质母细胞瘤（glioblastoma,GBM）是侵袭性极高、预后极差的中枢神经系统肿瘤。目前对于GBM的诊断主要依靠于影像学和组织活检。精准医学时代,液体活检这种相对无创的新兴检测手段已在诸多实体瘤中取得了显著的进展。与传统检测技术相比,液体活检弥补了传统组织活检有创和无法反复取样的局限。本文将针对液体活检循环肿瘤标志物如循环肿瘤DNA、microRNA、循环肿瘤细胞和外泌体在GBM 中的应用进展进行综述。     

基于肿瘤教化血小板的液体活检研究进展

随着人们生活水平提高以及生活方式的转变,癌症已经成为影响现代人寿命的主要原因之一。目前,临床医生通常根据临床表现、影像学检测和血液肿瘤标志物等对癌症进行初步诊断,确诊主要还是依赖于肿瘤组织的病理分析。但是病理组织取样属于侵入性操作,所以多种基于血液成分的液体活检被广泛应用于癌症的诊断,包括循环肿瘤DNA（circulating tumor DNA,ctDNA）、循环肿瘤细胞（circulating tumor cell,CTC）、细胞外囊泡（extracellular vesicles,EVs）和肿瘤教化血小板（tumor-educated platelets,TEPs）。TEPs在肿瘤早期诊断、治疗、进展与转移等领域发挥重要作用,具有较大的发展前景。本文将综述TEPs在各种肿瘤无创诊断、监测中的研究进展。      

ctDNA在肝细胞癌诊断、预后及治疗中的应用进展

精准医疗在肝细胞癌(HCC)中的应用有望改善不良预后和高死亡率，而液体活检为精准肿瘤学提供了良好的前景。循环肿瘤DNA(ctDNA)作为液体活检的重要组成部分，主要从原发肿瘤、转移灶的坏死细胞或凋亡细胞中释放，携带肿瘤细胞的基因变异信息，在肿瘤进展的早期阶段即可监测到，有助于及时反映患者的肿瘤负荷，在HCC早期诊断、疗效评价及预后分析中作为一种新型的肿瘤分子标志物具有巨大潜力。ctDNA检测是非侵入性的，具有无创、多时间点监测、肿瘤定性、耐药机制确定等优势，可支持对肿瘤进行实时、全方位的动态监测，以分析肿瘤复发、转移或治疗反应。本文就ctDNA在HCC诊断、预后预测及治疗中的应用研究进展作一综述。     

外泌体蛋白质在消化系统恶性肿瘤中的诊断价值

消化系统恶性肿瘤是人类常见的恶性肿瘤之一,其高发病率和晚期的低生存率给患者、家庭和社会带来沉重的疾病负担。然而,现有肿瘤筛查手段大多具有侵入性或操作复杂等特征,不利于开展大规模的人群筛查和长期随访,所以基于循环肿瘤DNA(circulating tumor DNA,ctDNA)、循环肿瘤细胞（circulating tumor cell,CTC）和外泌体（exosome）等新型生物标志物的液体活检技术具有广阔的发展前景。外泌体是由活细胞分泌、具有脂质双层膜的细胞外囊泡,相比于其他标志物其具有稳定性高、分布广泛、数量多等优势。外泌体携带的各种蛋白质能够反映来源细胞的特征,对于肿瘤早期诊断具有重要的研究价值。本文对近5年外泌体蛋白质作为消化系统恶性肿瘤早期诊断生物标志物的研究成果进行综述,并总结上述研究的主要特征和局限性,为促进外泌体蛋白质的临床转化提供参考依据。     

液态活检在胃癌诊治中应用的研究进展

作为一种新兴的非侵入式病理检测技术，“液态活检”主要包括循环肿瘤细胞、循环肿瘤DNA、微小RNA以及外泌体等生物标志物的无创检测，随着精准医学的发展，其在肿瘤早期诊断、监测疾病进展以及疗效评价等方面显示出丰富的应用价值。胃癌是我国常见的恶性肿瘤之一，发病率居消化系统肿瘤之首。临床诊治过程中，胃癌的早期诊断、疗效监测、疾病复发转移预警等方面仍存在困境，液态活检为我们在该领域提供了新的手段和方法，具有广阔的临床应用前景。本文就液态活检在胃癌诊治中应用的最新研究进展做一综述。     

循环肿瘤DNA在非小细胞肺癌中应用的研究进展

非小细胞肺癌（NSCLC）的靶向治疗及免疫治疗依赖于分子分型,但敏感基因及耐药基因的检测受困于组织活检取材困难及有创性等。循环肿瘤DNA（ctDNA）,作为一种无创性的“液体活检”手段,随着检测技术的进步,已显示良好的应用前景。本文将就ctDNA技术在非小细胞肺癌的诊断、靶向药物疗效预测及耐药监测等方面的研究及应用进展作一综述。     

Role of liquid biopsies in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, with a global incidence of over 1 million cases. In the era of personalized medicine, tumor sampling is essential for characterizing the molecular profile of individual tumors. This provides pivotal information regarding optimal sequencing of therapy and emergence of drug resistance, allowing for timely therapy adjustment. However, tumor tissue sampling offers static information in a single time point and area of disease at the time of biopsy, which may not entirely represent the heterogeneity of molecular alterations. Moreover, tumor biopsies often involve invasive procedures with potential risks to patients. Less invasive, safer, and real-time methods such as liquid biopsies have generated increasing interest as a surrogate of solid tumor biopsies. Liquid biopsy allows for noninvasive survey with detection of cell-free circulating tumor DNA (ctDNA) or circulating tumor cells. Blood-based assays are the most widely studied. Additionally, the quantity of ctDNA detected has been shown to correlate with tumor burden and enables assessment of tumor heterogeneity. In this article, we discuss the concept of liquid biopsies including ctDNA and circulating tumor cell, and their current application in the diagnosis and management of CRC. We suggest that liquid biopsies can be successfully used to characterize the molecular profile of CRC, monitor disease, detect minimal residual disease after surgery, and identify therapeutic targets and mechanisms of drug resistance. This strategy could potentially imply an early change in treatment, sparing unnecessary side effects, and minimizing health costs. Combined radiological and liquid biopsy assessments will likely become more standard in CRC oncology. However, large prospective studies are needed to definitively establish the role of liquid biopsy.     

The feasibility of using mutation detection in ctDNA to assess tumor dynamics

For many decades it has been known that tumor DNA is shed into the blood. As a consequence of technological limitations, researchers were unable to comprehensively characterize circulating DNA. The advent of ultrasensitive and highly specific molecular assays has provided a comprehensive profile of the molecular characteristics and dynamics of circulating DNA in healthy subjects and cancer patients. With these new tools in hand, significant interest has been provoked for an innovative type of tumor biopsy termed a “liquid biopsy”. Liquid biopsies are obtained by minimal invasive blood draws from cancer patients. Circulating cancer cells, exosomes and a variety of molecules contained within the liquid biopsy including cell‐free circulating tumor DNA (ctDNA) can serve as promising tools to track cancer evolution. Attractive features of ctDNA are that ctDNA isolation is straightforward, ctDNA levels increase or decrease in response to the degree of tumor burden and ctDNA contains DNA mutations found in both primary and metastatic lesions. Consequently, the analysis of circulating DNA for cancer‐specific mutations might prove to be a valuable tool for cancer detection. Moreover, the capacity to screen for ctDNA in serial liquid biopsies offers the possibility to monitor tumor progression and responses to therapy and to influence treatment decisions that ultimately may improve patient survival. Here we focus on mutation detection in ctDNA and provide an overview of the characteristics of ctDNA, detection methods for ctDNA and the feasibility of ctDNA to monitor tumor dynamics. Current challenges associate with ctDNA will also be discussed.     

Monitoring of cancer patients via next‐generation sequencing of patient‐derived circulating tumor cells and tumor DNA

Liquid biopsy of circulating tumor cells (CTC) and circulating tumor DNA (ctDNA) is gaining attention as a method for real‐time monitoring in cancer patients. Conventional methods based upon epithelial cell adhesion molecule (EpCAM) expression have a risk of missing the most aggressive CTC subpopulations due to epithelial‐mesenchymal transition and may, thus, underestimate the total number of actual CTC present in the bloodstream. Techniques utilizing a label‐free inertial microfluidics approach (LFIMA) enable efficient capture of CTC without the need for EpCAM expression. In this study, we optimized a method for analyzing genetic alterations using next‐generation sequencing (NGS) of extracted ctDNA and CTC enriched using an LFIMA as a first‐phase examination of 30 patients with head and neck cancer, esophageal cancer, gastric cancer and colorectal cancer (CRC). Seven patients with advanced CRC were enrolled in the second‐phase examination to monitor the emergence of alterations occurring during treatment with epidermal growth factor receptor (EGFR)‐specific antibodies. Using LFIMA, we effectively captured CTC (median number of CTC, 14.5 cells/mL) from several types of cancer and detected missense mutations via NGS of CTC and ctDNA. We also detected time‐dependent genetic alterations that appeared during anti–EGFR therapy in CTC and ctDNA from CRC patients. The results of NGS analyses indicated that alterations in the genomic profile revealed by the liquid biopsy could be expanded by using a combination of assays with CTC and ctDNA. The study was registered with the University Hospital Medical Information Network Clinical Trials Registry (ID: UMIN000014095).     

Patient monitoring through liquid biopsies using circulating tumor DNA

Tumors release components such as circulating tumor cells (CTCs), circulating tumor DNA (ctDNA), and tumor‐derived extracellular vesicles into the circulation. Multiple studies have demonstrated that molecular information about tumors and metastases can be extracted from these factors, which are therefore frequently referred to as “liquid biopsies.” Liquid biopsies allow the longitudinal monitoring of tumor genomes non‐invasively and may hence ensure that patients receive appropriate treatments that target the molecular features of their disease. Accordingly, the number of studies employing liquid biopsy based assays has been skyrocketing in the last few years. Here, we focus on three important issues, which are of high relevance for monitoring tumor genomes. First, we analyze the relation between the allele frequency of somatic tumor‐specific mutations and the tumor fraction within plasma DNA. Second, we ask how well current tumor evolution models correlate with findings in longitudinal liquid biopsy studies. And, finally, as sensitivity is one of the key challenges of mutation detection, we address the challenge of detecting mutations occurring at very low allele frequencies in plasma DNA.     

Detection and relevance of epigenetic markers on ctDNA: recent advances and future outlook

Liquid biopsy, a minimally invasive approach, is a highly powerful clinical tool for the real‐time follow‐up of cancer and overcomes many limitations of tissue biopsies. Epigenetic alterations have a high potential to provide a valuable source of innovative biomarkers for cancer, owing to their stability, frequency, and noninvasive accessibility in bodily fluids. Numerous DNA methylation markers are now tested in circulating tumor DNA (ctDNA) as potential biomarkers, in various types of cancer. DNA methylation in combination with liquid biopsy is very powerful in identifying circulating epigenetic biomarkers of clinical importance. Blood‐based epigenetic biomarkers have a high potential for early detection of cancer since DNA methylation in plasma can be detected early during cancer pathogenesis. In this review, we summarize the latest findings on DNA methylation markers in ctDNA for early detection, prognosis, minimal residual disease, risk of relapse, treatment selection, and resistance, for breast, prostate, lung, and colorectal cancer.     

液体活检在非小细胞肺癌靶向治疗中应用

目的液体活检技术在肿瘤的检测方法中是尤为重要的检测手段。其在指导非小细胞肺癌(non-small cell lung cancer,NSCLC)靶向药物的选择、耐药监测以及预后评估等方面具有重要作用,本研究分析近年来国内外液体活检在NSCLC靶向治疗中的应用,以期明确液体活检对NSCLC靶向治疗的指导作用,进而有助于指导靶向药物在NSCLC治疗中的应用。方法应用PubMed、中国知网及中国期刊全文数据库检索系统,以"液体活检、循环肿瘤DNA、循环肿瘤细胞、靶向治疗、非小细胞肺癌"为关键词,检索2009-2019年发表的相关文献。纳入标准:(1)液体活检的机制;(2)靶向治疗在NSCLC中的应用;(3)NSCLC的治疗。排除标准:(1)中文非核心期刊的文献和英文非SCI收录文献;(2)结果重复且相对陈旧的实验研究。根据纳入标准和排除标准,最终29篇文献纳入分析。结果液体活检技术可对NSCLC的诊断、治疗及预后评估进行实时动态监测,及时获取肿瘤基因突变信息,在指导靶向药物选择,对耐药监测以及预后评估等方面具有重要作用。结论液体活检对指导NSCLC患者的靶向治疗具有重要作用,有助于NSCLC患者靶向药物治疗的选择。