目前基于外泌体的癌症液体活检和基础研究往往以临床样品中的总外泌体为研究对象。其结果的可靠性受到体液中来自其他细胞的外泌体的干扰。运用抗体对特定外泌体进行纯化依赖于对该外泌体外膜特异性抗原的深入了解，当前对外泌体的认识限制了这一方法的实施。如何在对其外膜缺乏了解的情况下进行特定肿瘤来源的外泌体的分离成为一个亟需解决的问题。本课题组长期从事适配体的开发和应用工作，所建立的指数富集的配体进化（SELEX）平台可有效区分不同细胞之间的细微差别，为这一问题的解决带来了希望。本项目以乳腺癌外泌体为研究对象，通过对已有的SELEX平台进行改进，建立能够特异性识别乳腺癌外泌体的Exosome-SELEX平台。 本项目的实施将 1）拓宽SELEX技术的应用范围；2）提高乳腺癌液体活检的可靠性；3）揭示新的乳腺癌生物标记物，为乳腺癌的诊断和治疗提供依据；4）为其他癌症外泌体的分离和生物标记物的识别提供新方法。

Current exosome-based liquid biopsy and associated cancer research rely on analysis of the bulk exosomes from clinical samples. The reliability of such results is significantly influenced by the presence of exosomes derived from other dysregulated or normal cells. Identification and separation of tumor specific exosomes via antibody based immunological method requires the recognition of specific antigens or biomarkers of exosomes under study. Therefore, the ability to effectively separate tumor specific exosomes from clinical samples with limited knowledge of exosome membrane structure has become a particular challenge to overcome. Systematic evolution of ligands by exponential enrichment (SELEX) technique is able to effectively recognize minor differences between targets and therefore hold promise for solving this problem. In this study, we are planning to develop a novel Exosome-SELEX platform by applying breast cancer-derived exosomes as research models. The success of this project allows: (1) extending the application range of SELEX technique; (2) enhancing the reliability of exosome-based liquid biopsy of breast cancer; (3) providing a new strategy for the discovery of novel bio-markers of breast cancer and (4) generalizing the application of Exosome-SELEX platform to exosome separation and biomarker discovery of other types of cancers.