Background. PD-L1 expression is an important predictive factor of response to therapy with immune checkpoint inhibitors (ICIs). This study was designed to retrospectively analyze the concordance of PD-L1 measurements using three different assays (Dako22C3, Dako28-8, and SP142) in NSCLC patients and to find possible predictors of high PD-L1 expression. Materials and Methods. Data of 144 patients with histologically confirmed NSCLC and available PD-L1 measurements treated at the Taoyuan General Hospital from 2018 to 2019 were retrospectively reviewed in the study. Patients’ characteristics, including age, sex, clinical stage (T, N, and M) of NSCLC (AJCC, 8^th edition), and EGFR/ALK alterations, were analyzed for association with PD-L1 expression. Results. Measurements of PD-L1 expression levels with Dako22C3 and Dako28-8 were comparable while SP142 showed lower levels of PD-L1 expression. The overall agreement between Dako22C3 and Dako28-8 was 82.2% and 91.6% for both 1% and 50% TPS cut-offs, respectively. The above findings were confirmed by Cohen’s kappa. In addition, we found that PD-L1 expression was significantly associated with advanced N stage but not with T and M stages. Conclusion. Dako22C3 and Dako28-8 showed comparable results in assessing PD-L1 levels. Future prospective studies are needed to validate these findings. N stage may be a good predictor for PD-L1 expression.

中文翻译：

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PD-L1免疫组化可比性及其与NSCLC临床特征的相关性

背景。PD-L1 表达是免疫检查点抑制剂 (ICIs) 治疗反应的重要预测因素。本研究旨在回顾性分析在 NSCLC 患者中使用三种不同的检测方法（Dako22C3、Dako28-8 和 SP142）测量 PD-L1 的一致性，并寻找高 PD-L1 表达的可能预测因子。材料和方法。该研究回顾性分析了 2018 年至 2019 年在桃园总医院治疗的 144 名组织学证实的 NSCLC 患者和可用的 PD-L1 测量数据。^{分析了患者的特征，包括年龄、性别、NSCLC（ AJCC}，第 8 版）的临床分期（T、N 和 M）以及 EGFR/ALK 改变与 PD-L1 表达的关联。结果. Dako22C3 和 Dako28-8 对 PD-L1 表达水平的测量具有可比性，而 SP142 显示 PD-L1 表达水平较低。Dako22C3 和 Dako28-8 之间的总体一致性分别为 1% 和 50% TPS 截止值的 82.2% 和 91.6%。Cohen 的 kappa 证实了上述发现。此外，我们发现 PD-L1 表达与晚期 N 期显着相关，但与 T 和 M 期无关。结论。Dako22C3 和 Dako28-8 在评估 PD-L1 水平时显示出可比的结果。需要未来的前瞻性研究来验证这些发现。N 期可能是 PD-L1 表达的良好预测指标。