通过分析具有治疗抵抗性（TR）的视网膜母细胞瘤（RB）患者的血清小外泌体（sEVs），鉴定与TR相关的基因和途径，包括TR活跃型RB（TR-RB）和完全消退型RB（CR-RB）。使用透射电镜和纳米粒子追踪分析对血清来源的sEVs进行表征。将两例TR-RB患者和一例反应良好（>20年肿瘤无复发）的CR-RB患者的sEV转录组谱与与其年龄相配的对照组（n=3）进行比较。使用R Bioconductor软件包对基因表达数据进行分析。通过免疫组化和定量逆转录-聚合酶链反应研究了五例RB肿瘤和两例对照视网膜中CD9蛋白和CD9、CD63、CD81的mRNA表达。所分离的血清sEV呈圆形，尺寸在预期范围内（30-150 nm），其ζ电位在-10.8到15.9 mV之间。对于两位成人和四位儿童，sEV浓度的平均值±标准差为1.1×1012±0.1和5.8×1011±1.7个粒子/毫升。根据±2的log2折叠变化和P<0.05的标准，TR-RB中有492个非正常调节的基因，CR-RB中有184个。KAT2B、VWA1、CX3CL1、MLYCD、NR2F2、USP46-AS1、miR6724-4和LINC01257基因在TR-RB中特异性失调。负调节的凋亡信号、细胞生长和质子传输基因仅在TR-RB中超过5倍表达。RB肿瘤中CD9、CD63和CD81的mRNA水平高于对照视网膜，CD9的免疫活性在肿瘤的浸润区域呈增加和不稳定表达。血清sEVs可作为了解RB中TR机制的潜在液体活检来源。

To identify the genes and pathways responsible for treatment resistance (TR) in retinoblastoma (RB) by analyzing serum small extracellular vesicles (sEVs) of patients with TR active RB (TR-RB) and completely regressed RB (CR-RB).Serum-derived sEVs were characterized by transmission electron microscopy and nanoparticle tracking analysis. sEV transcriptome profiles of two TR-RB and one CR-RB with good response (>20 years tumor free) were compared to their age-matched controls (n = 3). Gene expression data were analyzed by the R Bioconductor package. The CD9 protein and mRNA expression of CD9, CD63, and CD81 were studied in five RB tumors and two control retinae by immunohistochemistry and quantitative reverse transcription-polymerase chain reaction.The isolated serum sEVs were round shaped and within the expected size (30-150 nm), and they had zeta potentials ranging from -10.8 to 15.9 mV. The mean ± SD concentrations of sEVs for two adults and four children were 1.1 × 1012 ± 0.1 and 5.8 × 1011 ± 1.7 particles/mL. Based on log2 fold change of ±2 and P < 0.05 criteria, there were 492 dysregulated genes in TR-RB and 184 in CR-RB. KAT2B, VWA1, CX3CL1, MLYCD, NR2F2, USP46-AS1, miR6724-4, and LINC01257 genes were specifically dysregulated in TR-RB. Negative regulation of apoptotic signaling, cell growth, and proton transport genes were greater than fivefold expressed only in TR-RB. CD9, CD63, and CD81 mRNA levels were high in RB tumors versus control retina, with increased and variable CD9 immunoreactivity in the invasive areas of the tumor.Serum sEVs could serve as a potential liquid biopsy source for understanding TR mechanisms in RB.