远处转移是鼻咽癌的主要死因，难点之一在于缺乏准确预测鼻咽癌转移的分子标志物。目前多采用血浆筛选分子标志物，但由于成分复杂，难以发现低丰度标志物。近期研究证实，血浆外泌体中可检测到疾病相关的低丰度蛋白。我们前期研究证明血浆外泌体与鼻咽癌远处转移密切相关，并通过质谱技术对鼻咽癌远处转移和非转移患者的血浆外泌体进行蛋白定量分析，成功筛选出差异表达蛋白34个，其中解旋酶DHX58表达差异最显著。细胞功能实验证实DHX58与鼻咽癌侵袭转移能力密切相关，Elisa法检测临床血浆标本发现DHX58预测鼻咽癌转移的准确度达70%。本项目拟进一步筛选其它外泌体转移相关蛋白，并通过随机生存树数学算法，构建一个由DHX58和其它标志物共同组成的转移预测模型，最大程度优化预测精度，并采用来源于前瞻性临床试验的大样本血标本进行验证，为早期预测鼻咽癌转移提供可靠的预测模型，为临床个体化治疗和诊断试剂盒研发提供理论依据

Distant metastasis is the major cause of death in nasopharyngeal carcinoma (NPC). One of the key reasons is a lack of biomarkers of NPC to predict the distant metastasis accurately. At present, hematologic specimens was routinely used to screen molecular markers but usually failed to find it with low abundance because the blood is an extremely complex biological samples, including more than 1,000,000 protein species. However, previous studies had showed that enriched plasma exosomes is helpful to find these low abundance biomarkers. Furthermore, we have demonstrated that the plasma exosomes are closely related with the distant metastasis of NPC. Therefore, we performed a quantitative analysis of proteins in plasma exosomes in NPC patients with distant metastasis vs. non-metastasis and successfully screened out 34 proteins with significantly differentially expression using the technology of SWATH mass spectrometry quantitative proteomic analysis method. Among those 34 protein, the expression of helicase DHX58 had most significant difference. Further cell experiments confirmed that DHX58 is closely related to the ability of invasion and metastasis of NPC cell. DHX58 is also proved to be efficient in predicting the distant metastasis with sensitivity and specificity of 68.6% and 71.4% based on plasma specimens with clinic data using Elisa method. This project aims to further screen out the rest exosome proteins associated tumor metastasis and set up a prediction Model for distant metastasis of NPC based on DHX58 and other metastasis-associated molecular markers to optimize prediction accuracy using random tree algorithm on survival. Finally, the prediction Model will be validated by large sample of blood specimen based on prospective clinical trials. This project will provide a promising and reliable prediction model for metastasis in NPC and theoretical basis for the development of the corresponding diagnostic kit.