Liquid biopsy involves the utilization of minimally invasive or noninvasive techniques to detect biomarkers in biofluids for disease diagnosis, monitoring, or guiding treatments. This approach is promising for the early diagnosis of childhood cancer, especially for brain tumors, where tissue biopsies are more challenging and cause late detection. Extracellular vesicles offer several characteristics that make them ideal resources for childhood cancer liquid biopsy. Extracellular vesicles are nanosized particles, primarily secreted by all cell types into body fluids such as blood and urine, and contain molecular cargos, i.e., lipids, proteins, and nucleic acids of original cells. Notably, the lipid bilayer-enclosed structure of extracellular vesicles protects their cargos from enzymatic degradation in the extracellular milieu. Proteins and nucleic acids of extracellular vesicles represent genetic alterations and molecular profiles of childhood cancer, thus serving as promising resources for precision medicine in cancer diagnosis, treatment monitoring, and prognosis prediction. This review evaluates the recent progress of extracellular vesicles as a liquid biopsy platform for various types of childhood cancer, discusses the mechanistic roles of molecular cargos in carcinogenesis and metastasis, and provides perspectives on extracellular vesicle-guided therapeutic intervention. Extracellular vesicle-based liquid biopsy for childhood cancer may ultimately contribute to improving patient outcomes.
液体活检是指利用微创或无创技术检测生物体液中的生物标志物，用于疾病诊断、监测或指导治疗。该方法在儿童癌症尤其是脑肿瘤的早期诊断中具有广阔前景，因为这类肿瘤的组织活检更具挑战性且易导致延迟发现。细胞外囊泡因其独特特性成为儿童癌症液体活检的理想资源。细胞外囊泡是纳米级颗粒，主要由各类细胞分泌至血液、尿液等体液中，其内部包含源细胞的脂质、蛋白质及核酸等分子物质。值得注意的是，细胞外囊泡的脂质双层膜结构能有效保护其内容物免受细胞外环境中酶解作用的影响。囊泡内的蛋白质与核酸可反映儿童癌症的基因变异和分子特征，因此为癌症诊断、治疗监测及预后预测等精准医疗领域提供了重要资源。本综述系统评估了细胞外囊泡作为液体活检平台在各类儿童癌症中的最新研究进展，探讨了其分子内容物在致癌与转移过程中的机制作用，并对基于细胞外囊泡的治疗干预策略提出展望。基于细胞外囊泡的儿童癌症液体活检技术有望最终改善患者临床结局。
肿瘤(癌症)患者之家