免疫检查点PD-1／PD-L1通路在小细胞肺癌中的作用

小细胞肺癌（SCLC）主要的特点为生长迅速且早期易发生广泛转移。尽管SCLC对于化疗和放疗敏感，但几乎所有的患者均在治疗后发生复发转移，预后差。免疫检测点抑制剂，尤其程序化细胞死亡受体-1（PD-1）／程序化细胞死亡配体-1（PD-L1）拮抗剂在SCLC的临床前和临床研究中均获得了良好效果，并且能够延长患者生存。免疫检测点疗法作为一种新兴的方法在未来可能会改变SCLC治疗模式。此外，有限的数据显示出PD-L1表达可能成为筛选获益人群一个有效的生物标记物。本文总结PD-L1作为标记物的发展历程，并同时阐述PD-1／PD-L1抑制剂在SCLC治疗中的进展。

The role of immune checkpoint PD-1/PD-L1 in small cell lung cancer

Small-cell lung cancer(SCLC)is characterized by its rapid growth and early development of widespread metastases.Although patients with SCLC are highly responsive to chemotherapy and radiation therapy,long-term prognosis remains poor,with relapse and disease metastasis occurring in almost all cases.Immune checkpoint blockade,especially blockade of programmed death-1(PD-1)receptor and its ligand PD-L1,achieved robust responses and improved survival for patients with SCLC in preclinical and clinical studies.The blockade of PD-1/PD-L1 pathway as a novel therapeutic approach may change the treatment paradigm of SCLC in the future.Data on clinical activity by programmed cell death-1 ligand expression in SCLC are not widely available.In addition,limited data indicate that PD-L1 expression may be an ideal biomarker for patient selection.Here,we summarize the brief history of PD-L1 as a biomarker and describe the critical role of PD-1/PD-L1 inhibitors in SCLC.