Checkpoint blockade therapy has emerged as a novel approach for cancer immunotherapy in several malignancies. However, patient prognosis and disease progression relevant to immune checkpoints in gastric tumor microenvironment are not defined. This study aims to investigate the expression and prognostic significance of immune checkpoints within gastric cancer. In the study, a cohort of 398 cancer tissues from stage I to IV gastric cancer patients were assessed for programmed cell death 1 ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) infiltration using immunohistochemistry to ascertain their survival correlation. The data revealed that higher TIL density correlated with less risk of disease progression, and exhibited survival benefits in gastric cancer patients, and PD-L1 positivity showed a significant association with the presence of high TIL infiltration. Furthermore, real-time quantitative polymerase chain reaction was performed to detect expression of multiple immune checkpoints with the relation to clinical outcome in 139 samples randomly selected from the same cohort, and higher messenger RNA levels of most immune checkpoints were associated with favorable outcome, while consistently showing a positive correlation with interferon gamma levels. In situ hybridization was used to determine the localization of Epstein–Barr virus (EBV) in 97 specimens, and showed EBV-positive gastric cancer samples correlated with PD-L1 expression and increased TIL density. These results suggest that induction of immune checkpoint within gastric cancer patients reflects a high immune infiltration density, especially in those with EBV-associated gastric cancer, which may direct patient selection for checkpoint blockade therapy.

在多种恶性肿瘤中，检查点封锁疗法已成为一种新的癌症免疫疗法。但是，与胃肿瘤微环境中免疫检查点相关的患者预后和疾病进展尚未明确。本研究旨在探讨免疫检查点在胃癌中的表达及其对预后的意义。在该研究中，使用免疫组织化学方法评估了一组从I期到IV期胃癌患者的398个癌症组织的程序性细胞死亡1配体1（PD-L1）表达和肿瘤浸润淋巴细胞（TIL）浸润，以确定它们的生存相关性。数据显示，较高的TIL密度与疾病进展的风险较小相关，并且在胃癌患者中显示出生存获益，PD-L1阳性与高TIL浸润显着相关。此外，实时定量聚合酶链反应用于检测多个免疫检查点的表达与临床结局的关系，该样本从同一队列中随机抽取139个样本，大多数免疫检查点的信使RNA水平较高与良好的结果相关，而一直显示与干扰素γ水平呈正相关。原位杂交用于确定97个标本中的爱泼斯坦-巴尔病毒（EBV）的定位，并显示EBV阳性胃癌样品与PD-L1表达和TIL密度增加相关。这些结果表明，在胃癌患者体内诱导免疫检查点反映出较高的免疫浸润密度，