肿瘤的复发转移是临床上较难克服的难题，我们前期发现C53在胃癌中呈低表达趋势，但是亦有约30%患者表达升高，胃癌组织中C53表达与肿瘤侵袭转移密切相关。查阅数据库发现人C53有5个异构体，我们前期研究发现大多数胃癌中主要表达C53-b和C53-e两个异构体，细胞功能实验显示两者在胃癌中的作用相反。根据生物信息学分析及预实验结果，我们提出C53不同异构体C53-b和C53-e通过与UFM1相互作用在胃癌侵袭转移中发挥不同生物学功能的理论假设。本项目利用特异性的抗体和引物检测胃癌中不同异构体表达情况；用细胞转染、报告基因、功能挽救等实验研究C53不同异构体对胃癌侵袭迁移的影响；并进一步探讨C53-b和C53-e与UFM1的相互作用关系，及UFM1在C53-b和C53-e不同生物学功能中的作用，从而阐明C53-b和C53-e对胃癌侵袭转移不同作用的分子机制，为胃癌治疗提供新的候选靶点和干预手段。

The recurrence and metastasis of tumor has long been a difficult clinical problem. We found that C53 expression was markedly decreased in gastric tumor tissue. However, about 30% patients showed increased expression. The expression of C53 was associated with tumor invasion and metastasis. There are five isoforms of human C53 from the NCBI and Gene database. In our previous assay, we found that most of the gastric cancers mainly express two isoforms, C53-b and C53-e, and these two isoforms had opposite functions in gastric cancer. Based on bioinformatics analysis and preliminary experimental results, we proposed the theoretical hypothesis that the isoforms C53-b and C53-e interact with UFM1, and play different biological roles in the invasion and migration of gastric cancer. This project will further identify the expression of different isoforms of C53 in gastric cancer by using characteristic antibodies and primers. The effects of C53 isoforms on invasion and metastasis of gastric cancer will be explored using cell transfection, reporter gene and functional rescue; we will explore the interactions between C53-b, C53-e and UFM1, and investigate the effect and mechanism of UFM1 on C53-b and C53-e, by which invasion and migration of gastric cancer is promoted. This study will provide a theoretical foundation for designing and developing new drugs to treat gastric cancer.