Laboratory Medicine Department, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain.
Molecular Oncology Laboratory, Biomedical Sciences Research Institute, Hospital Universitario Puerta de Hierro-Majadahonda, Madrid, Spain.
Clin Chem Lab Med. 2021 Mar 11;59(7):1221-1229. doi: 10.1515/cclm-2020-1465. Print 2021 Jun 25.
Epidermal growth factor receptor () biomarker testing using blood-based liquid biopsies remains challenging due to the low concentration of circulating tumor DNA (ctDNA) in certain plasma samples. The aim of this study is to evaluate the usefulness for biomarker testing of ctDNA from pleural effusions, cerebrospinal fluids, ascites and pericardial effusions obtained during the clinical management of lung adenocarcinoma patients.
For comparison purposes, 23 paired plasma and body fluid samples were collected from 17 patients with -positive lung adenocarcinoma. After circulating free DNA (cfDNA) isolation, samples were evaluated for the initial -sensitizing mutation and the p.T790M resistance mutation by array-based digital PCR (dPCR).
Body fluids had more cfDNA than plasma samples (1.90 vs. 0.36 ng/µL; p=0.0130), and more samples tested positive for mutations (21 vs. 16 samples), with a total of 28 vs. 22 variants detected. Furthermore, mutant allele frequencies (MAFs) observed in body fluids were significantly higher than those assessed in the paired plasma samples for -sensitizing mutations (median MAFs = 15.8 vs. 0.8%; p=0.0004) as well as for the p.T790M resistance mutation (median MAFs = 8.69 vs. 0.16%; p=0.0390). Importantly, two patients who had progressed on first-generation -tyrosine kinase inhibitors with a dubious result for p.T790M plasma (MAFs = 0.11%) had an indisputably positive result in their respective body fluid samples (MAFs = 10.25 and 9.66%).
ctDNA derived from body fluids is an informative source for biomarker testing, with greater sensitivity than plasma samples.
由于某些血浆样本中循环肿瘤 DNA（ctDNA）的浓度较低，使用基于血液的液体活检进行表皮生长因子受体（）生物标志物检测仍然具有挑战性。本研究旨在评估从胸腔积液、脑脊液、腹水和心包积液中获得的 ctDNA 用于检测肺腺癌患者临床管理中获得的 ctDNA 的有用性。
为了比较目的，从 17 名阳性肺腺癌患者中收集了 23 对血浆和体液样本。在分离游离循环 DNA（cfDNA）后，通过基于阵列的数字 PCR（dPCR）评估样本中初始敏感突变和 p.T790M 耐药突变。
体液中的 cfDNA 多于血浆样本（1.90 与 0.36 ng/µL；p=0.0130），并且更多的样本检测到突变（21 与 16 个样本），总共检测到 28 个与 22 个变体。此外，与配对血浆样本相比，体液中观察到的突变等位基因频率（MAF）对于敏感突变（中位数 MAFs=15.8 与 0.8%；p=0.0004）以及 p.T790M 耐药突变（中位数 MAFs=8.69 与 0.16%；p=0.0390）显著更高。重要的是，两名在第一代 - 酪氨酸激酶抑制剂治疗后进展且 p.T790M 血浆检测结果可疑的患者（MAFs=0.11%）在各自的体液样本中均有明确的阳性结果（MAFs=10.25 和 9.66%）。
来自体液的 ctDNA 是一种用于检测生物标志物的信息丰富的来源，其敏感性高于血浆样本。
