Background:The detection of circulating tumor cells (CTCs) holds significant promise for the diagnosis and monitoring of lung cancer (LC). However, the clinical utility of CTCs is limited by the heterogeneity of their phenotypes and the shortcomings of existing detection methods, which often rely on epithelial markers like EpCAM. DNA aptamers offer a promising alternative due to their high affinity, stability, and ability to recognize diverse cancer-specific biomarkers.Methods:This study utilized DNA aptamers LC-17 and LC-18, previously selected against primary lung tumor tissue, to isolate and detect CTCs in the peripheral blood of 43 non-small cell lung cancer (NSCLC) patients. Mass spectrometry (LC-MS/MS) was employed to identify the target proteins of aptamer LC-17. CTCs from patients’ blood and healthy donors were isolated via filtration after erythrocyte and lymphocyte lysis and stained with FAM-labeled LC-17 and LC-18 aptamers for detection using fluorescence and light microscopy.Results:Mass spectrometry identified neutrophil defensin 1 (DEFA1) and peroxiredoxin-2 (PRDX2) as the primary protein targets of aptamer LC-17 in CTCs, both of which were absent in healthy donor samples. CTC enumeration revealed statistically significant correlations between elevated CTC counts (>3 cells/4 mL blood) and advanced primary tumor size (T4 vs. T1–T3,p= 0.012), extensive regional lymph node metastasis (N3 vs. N1–N2,p= 0.014), and shorter overall survival (median 24 vs. 32 months,p< 0.05).Conclusions:The developed aptamer-based liquid biopsy method effectively captures heterogeneous CTC populations independent of EpCAM expression. The strong correlation of CTC counts with disease progression and survival underscores their clinical relevance as a prognostic biomarker in NSCLC. This approach presents a viable, non-invasive tool for disease monitoring and stratification of NSCLC patients, with potential for integration into clinical practice.
背景：循环肿瘤细胞（CTCs）的检测在肺癌（LC）的诊断与监测中具有重要前景。然而，CTCs的临床应用受限于其表型异质性以及现有检测方法的不足，这些方法通常依赖于EpCAM等上皮标志物。DNA适配体因其高亲和力、稳定性及识别多种癌症特异性生物标志物的能力，成为一种有前景的替代工具。 方法：本研究利用先前针对原发性肺肿瘤组织筛选出的DNA适配体LC-17和LC-18，对43例非小细胞肺癌（NSCLC）患者外周血中的CTCs进行分离与检测。采用质谱分析（LC-MS/MS）鉴定了适配体LC-17的靶蛋白。通过红细胞和淋巴细胞裂解后过滤分离患者血液及健康供体样本中的CTCs，并使用FAM标记的LC-17和LC-18适配体进行染色，通过荧光及光学显微镜进行检测。 结果：质谱分析鉴定出中性粒细胞防御素1（DEFA1）和过氧化物还原酶-2（PRDX2）为适配体LC-17在CTCs中的主要蛋白靶标，这两种蛋白在健康供体样本中均未检出。CTCs计数分析显示，CTCs数量升高（>3个细胞/4 mL血液）与原发性肿瘤体积较大（T4对比T1–T3，p=0.012）、区域淋巴结广泛转移（N3对比N1–N2，p=0.014）以及较短的总生存期（中位生存期24个月对比32个月，p<0.05）之间存在统计学显著相关性。 结论：本研究开发的基于适配体的液体活检方法能够有效捕获不依赖于EpCAM表达的异质性CTCs群体。CTCs数量与疾病进展及生存期的强相关性，凸显了其作为NSCLC预后生物标志物的临床意义。该方法为NSCLC患者的疾病监测与分层提供了一种可行、非侵入性的工具，并具有融入临床实践的潜力。
Targeting CTC Heterogeneity: Aptamer-Based Liquid Biopsy Predicts Outcome in Lung Cancer
肿瘤(癌症)患者之家