There are currently two main types of clinically available liqui
There are currently two main types of clinically available liquid biopsy:
Circulating tumor cell count (CTC)—these tests look at whole tumor cells in the blood to help determine prognosis in breast, colon, or prostate cancer that has spread to nearby or distant organs (metastatic). They may also be used to evaluate responses to therapy for those cancers. Circulating tumor DNA (ctDNA)—these tests look for tumor DNA that cancer cells release into the blood. An example is an FDA-approved test that is used to decide if anti-EGFR medications (erlotinib or osimertinib) can be used to treat non-small-cell lung cancer.
"Like all new things in medicine, the use of ctDNA assays in routine cancer care requires evidence of clinical utility. At present, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer, including those that interrogate a panel of genes," said Daniel F. Hayes, MD, coauthor of the review, who was representing ASCO.
"What is promising is that this area of research is rapidly evolving, so there should be enough evidence soon to formulate evidence-based guidance for a variety of clinical scenarios,"
简单说，现在的技术有两个关键：液体活检和NGS（新一代测序技术）
NGS的关键是可以同时分析数以百万计的基因片段，不需要从头到尾一点一点的测序，甚至可以同一个样品中检测很多人样品来源。当然，你可以想象这对大数据处理能力的要求有多么苛刻
液体活检：不用传统的采样方法（手术组织活检），只需10ml血液就可以。我知道，有些人会觉得不可能，癌症基因突变是发生在肿瘤组织，血液样品来源的DNA是正常组织。没错，但是，这就是现在这个技术炒的火热，拼命有人投钱的原因。原理是，无论肿瘤发生在哪里，总有癌症细胞会自然死亡，死亡细胞的碎片会进入血液，这可以理解吧？所以，这个技术的关键就是，找出这些癌变细胞来源的DNA碎片。大海捞针，难就难在这里。这个实验的第一步就是离心，分离血清，除去血细胞污染。抱歉只能说这么多了。
有时候（下面的例子）同时取肿瘤活检样品，是为了做对照实验，分析液体活检的误差和灵敏度
现在的问题有两个，一个是对于操作技术的要求非常高。有多高？同样的仪器设备，同样的药剂，同样的操作规程，经过专门培训，中国依然做不了。你看一下那个公司的人员，基本都是国外回去的。第二个问题是成本太高。由于这两个原因，现阶段很难规范化和标准化，无法大规模投入使用。
你知道的一个应用是靶向药物治疗。但是，如果这个技术成熟了，可以用作大规模癌症的早期筛选和检测，多少人等着发这个财。
There are currently two main types of clinically available liquid biopsy:
Circulating tumor cell count (CTC)—these tests look at whole tumor cells in the blood to help determine prognosis in breast, colon, or prostate cancer that has spread to nearby or distant organs (metastatic). They may also be used to evaluate responses to therapy for those cancers.
Circulating tumor DNA (ctDNA)—these tests look for tumor DNA that cancer cells release into the blood. An example is an FDA-approved test that is used to decide if anti-EGFR medications (erlotinib or osimertinib) can be used to treat non-small-cell lung cancer.
谢谢分享。
你提到的这个基因检测技术，曾听过这方面的一个讲演，至于现在的临床应用到啥程度，我不是太清楚。
感觉比如大多癌症属中期后的，没准液体活检可以； 还有就是肺癌，癌细胞碎片是属较其它种癌症易进入血液的癌种。
至于其它种类癌症，若属早期原位，还是得用手术组织活检吧，用这类液体活检来替代当肿瘤本身的突变检测，恐怕现在的技术还没那么准确吧？
有一家基因检测公司终于上市了，股票价值十几亿，公司召开庆祝活动，大家喝酒唱歌很开心
记者无意看到公司老总一个人在外面抽烟，心想，不愧是老总啊，这时候也这么镇定
记者上去搭讪：X总，公司上市带来这么多资金，你们有什么打算？
老总说，打算？先把欠的债还了
那剩下的呢？记者接着问
剩下的？老总吐了一个烟圈说，剩下的以后再还！
临床上要求的是用最经济简单的方法得到最大效益。
得不到肿瘤组织的情况下才用liquid biopsy 的方法试试。
至于应用于哪一类癌症，关键是癌变基因本身的多样性。现在的检测是已经发现的变异类型，如果变异类型少就容易，变异类型多，检测量就要很大，对于技术灵敏度和误差范围要求就更高了。
目前来说，用其它方法，如成像，手术可以发现的癌症，液体活检都可以检测到。现在是希望在用其它方法可以发现肿瘤之前，可以用液体活检早期发现并用于大规模筛选。中国已经启动了这个技术用于乳腺癌早期检测的试验
这种公司看来还不少，技术高低不一。国家应该规范一下了，各地选取相对比较成熟的公司作为指定公司。问题是，这些制定规范的人，谁来规范？
作为一个医师连自己的情志都不注意改善，请你自己检视一下自己的发言。这样下去对健康不利。自视再高也不能妄自尊大，口无遮拦。
"Like all new things in medicine, the use of ctDNA assays in routine cancer care requires evidence of clinical utility. At present, there is insufficient evidence of clinical validity and utility for the majority of ctDNA assays in advanced cancer, including those that interrogate a panel of genes," said Daniel F. Hayes, MD, coauthor of the review, who was representing ASCO.
"What is promising is that this area of research is rapidly evolving, so there should be enough evidence soon to formulate evidence-based guidance for a variety of clinical scenarios,"
Liquid Biopsies Not Yet Ready for Prime Time, Says Expert Review
Circulating Tumor DNA Analysis in Patients With Cancer: American Society of Clinical Oncology and College of American Pathologists Joint Review
用liquid biopsy找治疗靶点是试验性的吧？感觉如果有活体组织舍弃不用，而用血液找治疗靶点好像比较奇怪。