靶向免疫检查点PD-1/PD-L1的肿瘤分子影像学研究进展

程序化细胞死亡受体-1（PD-1）及其配体（PD-L1）抑制剂通过阻断PD-1与PD-L1的结合使负向调控信号受阻，重新激活T淋巴细胞，增强免疫应答。临床试验结果显示PD-1/PD-L1抑制剂对多种肿瘤有明确的疗效，且疗效与肿瘤PD-1/PD-L1的表达水平相关。因此在免疫治疗之前检测患者PD-1/PD-L1的表达水平对筛选可能获益的患者、预测免疫治疗反应尤为重要。靶向PD-1/PD-L1的分子影像学方法能够在活体内无创、全面、准确地显示肿瘤PD-1及PD-L1的表达水平，成为国内外的研究热点。笔者对靶向PD-1/PD-L1肿瘤分子影像学的研究进展作一综述。

Advances of molecular imaging of immune checkpoint targeting PD-1/PD-L1 in tumors

Programmed cell death-1 (PD-1) and its ligand (PD-L1) inhibitors can inhibit the PD-1 and PD-L1 combination to block negative control signals. This condition leadings to the activity of T lymphocytes and the enhancement of immune responses. Clinical studies have shown that PD-1/PD-L1 inhibitors have a definite effect on a broad set of malignancies, but a substantial number of patients do not respond. Predicting the immunotherapy response by evaluating the expression of PD-1 and PD-L1 is urgently needed. Molecular imaging modalities, such as PET, SPECT, optical imaging, and MRI, can noninvasively and dynamically detect the overall expression of PD-1/PD-L1 in patients. They can help in selecting patients who are suitable for immunotherapy and monitor the tumor response. This review describes the current status and progress of molecular imaging targeting PD-1/PD-L1 in tumors.