胞外体是真核细胞在正常生理过程中分泌的一种具有多种细胞膜结构的小囊泡,作为一类重要的细胞间信号分子,胞外体具有多种生物活性成分,其异常分泌是恶性肿瘤的标志.胞外体与肿瘤细胞生长、肿瘤血管生成、免疫抑制及化疗耐药关系密切.因此,探究胞外体的形成过程、主要组成成分及肿瘤相关的胞外体在肿瘤进展、免疫调节中的作用有助于进一步了解肿瘤进展过程,具有重要意义.“,”Exosome is a type of microvesicles with bilayer structure,which secreted by many different cell types under physiological status.As an important signaling mediator of cell communication,exosomes possess various of activities,while exosome secretion is a notable characteristic of malignancy.So far,exosomes have association with tumor cell proliferation,tumor angiogenesis,immune tolerance and chemotherapy resistance.This review focuses on exosome forming process,major components,and the lastest researches on the role of tumor-associated exosomes in tumor development,immune regulation.