BACKGROUND Programmed death-ligand 1 (PD-L1) is a programmed death 1 (PD-1) ligand that plays a pivotal role in the inhibition of the T-cell-mediated immune response. The expression of PD-L1 is associated with the prognosis and clinical outcomes of multiple tumors. However, the prognostic value of PD-L1 overexpression in colorectal cancer is still controversial. In this study, we sought to clarify this by presenting a meta-analysis of relevant studies. METHODS Databases including PubMed, Web of Science, and EMBASE were systematically searched for studies concerning the expression of PD-L1 and survival in colorectal cancer. The reported hazard ratios (HR) with 95% confidence intervals (CI) of overall survival, disease-free survival, and recurrence-free survival in the included studies were analyzed by fixed effects/random effects models. RESULTS Fifteen studies involving 3078 patients with colorectal cancer were included in our meta-analysis. Overexpression of PD-L1 was found to be associated with poor overall survival (HR 1.83; 95% CI 1.21, 2.79; P = 0.005) and poor recurrence-free survival (HR 2.78; 95% CI 1.43, 5.42; P = 0.003). However, no correlation was found between PD-L1 overexpression and poor disease-free survival (HR 1.23; 95% CI 0.83, 1.82; P = 0.305). Overexpression of PD-L1 indicating poor survival held true across different geographical areas, sample sizes, analysis types, sources of HRs, and cell types. CONCLUSION Overexpression of PD-L1 is associated with worse prognosis in patients with colorectal cancer and can guide physicians in the application of PD-1/PD-L1 immune checkpoint-targeted therapy.

中文翻译：

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程序性死亡配体 1 和结直肠癌的生存：一项荟萃分析。

背景 程序性死亡配体 1 (PD-L1) 是一种程序性死亡 1 (PD-1) 配体，在抑制 T 细胞介导的免疫反应中起关键作用。PD-L1的表达与多种肿瘤的预后和临床结局相关。然而，PD-L1过表达在结直肠癌中的预后价值仍存在争议。在这项研究中，我们试图通过对相关研究的荟萃分析来澄清这一点。方法 系统检索包括 PubMed、Web of Science 和 EMBASE 在内的数据库，以查找有关 PD-L1 表达和结直肠癌生存率的研究。通过固定效应/随机效应模型分析纳入研究中报告的总生存期、无病生存期和无复发生存期的风险比 (HR) 和 95% 置信区间 (CI)。结果 我们的荟萃分析纳入了涉及 3078 名结直肠癌患者的 15 项研究。发现 PD-L1 的过表达与较差的总生存期 (HR 1.83; 95% CI 1.21, 2.79; P = 0.005) 和较差的无复发生存期 (HR 2.78; 95% CI 1.43, 5.42; P = 0.003) 相关. 然而，在 PD-L1 过表达与较差的无病生存率之间没有发现相关性（HR 1.23；95% CI 0.83，1.82；P = 0.305）。PD-L1 的过度表达表明在不同的地理区域、样本量、分析类型、HR 来源和细胞类型中存在较差的存活率。结论 PD-L1过表达与结直肠癌患者预后不良相关，可指导医师应用PD-1/PD-L1免疫检查点靶向治疗。