鼻咽癌（NPC）是我国南方和东南亚高发的一种恶性肿瘤，揭示其癌变机理、寻找早期诊断的分子标志物对提高NPC的整体疗效十分关键。前期工作中，我们以NPC细胞系5-8F为靶细胞，用cell-SELEX技术筛选获得了特异性靶向NPC的核酸适配体S3，鉴定出其靶蛋白是CD109分子。初步的研究结果表明，CD109在所检测的NPC组织中均表达，而在慢性鼻咽炎上皮组织中基本不表达。本课题将以CD109为中心，深入研究其在NPC中的表达、调控机制、功能及作用分子机制，并利用荧光标记的核酸适配体S3对NPC裸鼠移植瘤的体内成像及对患者循环肿瘤细胞的检测进行NPC早期诊断的初步探索。本研究对于进一步阐明NPC发生发展的分子机制具有重要意义，对于发展新的NPC早期诊断策略具有重要价值。

Nasopharyngeal carcinoma (NPC) is a malignancy with high incidence in southern China and Southeast Asia. It is crucial to reveal its mechanisms of carcinogenesis and find better molecular biomarkers for early diagnosis in order to improve the overall curative effects of NPC. In previous study, we successfully obtained a NPC specific aptamer named as S3 by cell-SELEX using NPC cell line 5-8F as target cells. CD109 was identified as the target protein of aptamer S3. Our preliminary study showed that CD109 was expressed in all the detected NPC tissues, but almost not in chronic nasopharyngitis epithelia. In this project, we will focus on CD109 and in depth investigate its expression, regulatory mechanisms, functions and action mechanisms in NPC. Fluorophore labeled S3 will be applied for in vivo imaging of transplanted NPC cells in nude mice and for detection of circulating tumor cells in NPC patients. This project will contribute to further clarifying the mechanisms of NPC occurrence and progression, and be of great significance to develop new method and strategy for early diagnosis of NPC.