肿瘤的发生是一个多因素、多步骤的过程。肿瘤细胞通过抑制机体的抗肿瘤免疫应答，实现免疫逃逸，促进肿瘤生长。肿瘤免疫逃逸的分子机制是肿瘤免疫研究的核心问题之一。在T细胞介导的免疫反应中，程序性死亡受体-1（programmed death receptor-1，PD-1）是关键的抑制性免疫检查点。肿瘤通过表达程序性死亡配体-1（programmed death ligand-1，PD-L1），可以增强PD-1抑制信号，促进肿瘤免疫逃逸。研究肿瘤细胞如何调节PD-L1表达，有助于阐明肿瘤发生免疫逃逸的分子机制。近年来的研究发现，肿瘤细胞在基因转录、转录后调节以及蛋白翻译后修饰等多个环节对PD-L1表达进行调节，并且通过调控PD-L1的表达影响抗肿瘤免疫反应。这些研究为肿瘤免疫治疗提供了新的靶点。

Tumorigenesis is a complex process involving multistep. Tumor cells escape from immune of the host and promote their proliferation via inhibiting antitumor immune responses of the host. Molecular mechanism of the tumor immune escape is one of core issues about the tumor immune research. Programmed death receptor-1 (PD-1) is a key checkpoint for the inhibit immunity. The tumors can enhance inhibit signal of PD-1 and promote their immune escape through expression of programmed death ligand-1 (PD-L1). Research on how tumor cells regulate expression of PD-L1 can help to expound molecular mechanism of the tumor immune escape. Recently, some researches found tumor cells regulate expression of PD-L1 on multisteps of gene translation, post-transcriptional regulation and post-translational modification of proteins, as well as affect the anti-tumor immune responses through regulating expression of PD-L1. The researches provided novel targets for the immunotherapy of tumors.

国家重点研发计划课题（No.2016YFA0502201）