脑癌是儿童癌症相关死亡的主要原因。早期检测和连续监测对于获得更好的治疗结果至关重要。最近，液态活检已成为一种有前途的方法，通过筛查体液中循环肿瘤DNA（ctDNA）的存在来检测这些肿瘤。在这里，我们使用患者特定的体细胞突变来检测和监测儿童原发性和转移性脑癌的限制。在3个室管膜瘤、1个多层玫瑰胚胎性肿瘤、1个中枢神经系统神经母细胞瘤和7个小脑母细胞瘤患者中发现了体细胞突变。使用这些突变作为液态生物标志物对脑脊液（CSF）样本进行连续评估，使用微滴数字PCR（ddPCR）系统。为了评估该方法的临床转化效用，结果与成像数据和临床评估进行了相关。我们开发了个性化体细胞突变ddPCR检测，我们证明这些检测在ctDNA的检测和监测方面具有很高的特异性、敏感性和效率，大多数患者中存在ctDNA与疾病病程和临床结果呈正相关。我们展示了个性化突变基础液态生物检测在监测儿童脑癌中的可行性和临床效应。然而，即使采用这种特异性和敏感性的方法，我们仍然发现了一些可能的假阴性分析。总的来说，我们的结果表明，随着时间的推移，ctDNA资料的变化显示了我们的特异性方法预测肿瘤进展、负担和对治疗的反应的巨大潜力。©作者（2023年）Oxford大学出版社代表神经肿瘤学会发表。

Brain cancer is the leading cause of cancer-related death in children. Early detection and serial monitoring are essential for better therapeutic outcomes. Liquid biopsy has recently emerged as a promising approach for detecting these tumors by screening body fluids for the presence of circulating tumor DNA (ctDNA). Here we tested the limits of liquid biopsy using patient-specific somatic mutations to detect and monitor primary and metastatic pediatric brain cancer.Somatic mutations were identified in 3 ependymoma, 1 embryonal tumor with multilayered rosettes, 1 central nervous system neuroblastoma and 7 medulloblastoma patients. The mutations were used as liquid biomarkers for serial assessment of cerebrospinal fluid (CSF) samples using a droplet digital PCR (ddPCR) system. The findings were correlated to the imaging data and clinical assessment to evaluate the utility of the approach for clinical translation.We developed personalized somatic mutation ddPCR assays which we show are highly specific, sensitive and efficient in detection and monitoring of ctDNA, with a positive correlation between presence of ctDNA, disease course and clinical outcomes in the majority of patients.We demonstrate the feasibility and clinical utility of personalized mutation-based liquid biopsy for the surveillance of brain cancer in children. However, even with this specific and sensitive approach, we identified some potential false negative analyses. Overall, our results indicate that changes in ctDNA profiles over time demonstrate the great potential of our specific approach for predicting tumor progression, burden, and response to treatment.© The Author(s) 2023. Published by Oxford University Press on behalf of the Society for Neuro-Oncology.