肿瘤治疗过程中会出现很多严重的不良反应，如何将药物特异性导向癌细胞就成为了肿瘤治疗中亟需解决的问 题。外泌体是由细胞分泌的、纳米级别的、双层脂质的盘状囊泡结构。正常细胞与肿瘤细胞均可分泌外泌体，供体细胞分泌的 外泌体携带着蛋白质、脂质和核糖核酸（包括microRNA和lncRNA），可直接被同组织内其周围的受体细胞所吸收；同时外泌体 几乎存在于唾液、血液、尿液、脑脊髓液等所有体液中，通过体液运输被不同组织内受体细胞所吸收，为受体细胞的生长提供必 要的营养物质。肿瘤细胞中往往可对外释放出高于正常组织的外泌体，在肿瘤发展过程中外泌体对肿瘤的生长、转移和血管 生成起到重要的作用；同时癌细胞所分泌的外泌体中有着可用来区别与其他细胞外泌体不同的特征性分子，可作为肿瘤临床 诊断的分子标志物，也可作为肿瘤分级、精准治疗及预后评估的重要依据。鉴于此，本文收集国外内相关研究资料，对外泌体 的生物学特征进行总结，并综述了其在临床肿瘤诊断、治疗中的作用及应用潜力，并对外泌体进一步的发展方向进行展望，以 期能为外泌体在临床肿瘤精准治疗中的应用提供理论支持。

The current methods of treating cancer have serious side effects. Therefore, how to specifically target the drug to cancer cells has become an urgent problem in cancer treatment. Exosomes are disc⁃shaped vesicles secreted by cells at a nanometer level and with double lipid layers. Both normal cells and tumor cells can secrete exosomes. The exosomes secreted by donor cells carry proteins, lipids and ribonucleic acid (including microRNA and lncRNA), which can be directly absorbed by recipient cells in the same tissue. At the same time, exosomes exist in almost all body fluids such as saliva, blood, urine, and cerebrospinal fluid, and are absorbed by receptor cells in different tissues through body fluid transportation, and provide necessary nutrients for the growth of recipient cells. Tumor cells can often release exosomes that are higher than normal tissues. Exosomes play an important role in tumor growth, metastasis and angiogenesis during the development of cancer. At the same time, there are exosomes secreted by cancer cells. It can be used to distinguish characteristic molecules that are different from other cellular exosomes, can be used as a molecular marker for tumor clinical diagnosis, and can also be used as an important basis for tumor grading, precise treatment and prognostic evaluation. In view of this, this article collects relevant research data abroad, summarizes the biological characteristics of exosomes, and summarizes its role and application potential in clinical tumor diagnosis and treatment, and prospects for the further development of exosomes, in order to provide theoretical support for the application of exosomes in clinical tumor precision treatment.