Objectives: Anti–programmed cell death 1 (PD‐1)/programmed death ligand 1 (PD‐L1) immunotherapy has demonstrated success in the treatment of advanced NSCLC. Recently, PD‐1/PD‐L1 blockade also has demonstrated interesting results in small trials of neoadjuvant treatment in stage IB to IIIA NSCLC. In addition, several clinical trials using anti–PD‐1/PD‐L1 immunotherapy as an adjuvant or neoadjuvant treatment in patients with resectable stage NSCLC are ongoing. However, few analyses of anti–PD‐1/PD‐L1 immunotherapy–related biomarkers in early‐stage squamous cell lung carcinoma (SqCLC) have been reported. In this study, we evaluated PD‐L1 protein expression, tumor mutation burden, and expression of an immune gene signature in early‐stage SqCLC, providing data for identifying the potential role for patients with anti–PD‐1/PD‐L1 treatment in early‐stage SqCLC. Methods: A total of 255 specimens from patients with early‐stage SqCLC were identified within participating centers of the Strategic Partnering to Evaluate Cancer Signatures program. PD‐L1 protein expression by immunohistochemistry was evaluated by using the Dako PD‐L1 22C3 pharmDx kit on the Dako Link 48 auto‐stainer (Dako, Carpinteria, CA). Tumor mutation burden (TMB) was calculated on the basis of data from targeted genome sequencing. The T‐effector and interferon gamma (IFN‐&ggr;) gene signature was determined from Affymetrix gene chip data (Affymetrix, Santa Clara, CA) from frozen specimens. Results: The prevalence of PD‐L1 expression was 9.8% at a tumor proportion score cutoff of at least 50%. PD‐L1 mRNA and programmed cell death 1 ligand 2 mRNA positively correlated with PD‐L1 protein expression on tumor cells (TCs) and tumor‐infiltrating immune cells. PD‐L1 protein expression on tumor‐infiltrating immune cells was correlated with the T‐effector and IFN‐&ggr; gene signature (p < 0.001), but not with TMB. For TCs, all of these biomarkers were independent of each other and neither PD‐L1 protein expression, TMB, or T‐effector and IFN‐&ggr; gene signatures were independently prognostic for patient outcomes. Conclusions: Evaluation of PD‐L1 expression, TMB, and T‐effector and IFN‐&ggr; gene signatures in the cohort with early‐stage SqCLC found them to be independent of each other, and none was associated with overall survival. Our results also support the hypothesis that PD‐L1 expression is regulated by an intrinsic mechanism on TCs and an adaptive mechanism on immune cells.

中文翻译：

---

早期鳞状细胞肺癌 PD-L1 表达与肿瘤突变负荷和基因特征的相关性

目的：抗程序性细胞死亡 1 (PD-1)/程序性死亡配体 1 (PD-L1) 免疫疗法已证明在治疗晚期 NSCLC 方面取得成功。最近，PD-1/PD-L1 阻断剂也在 IB 至 IIIA 期 NSCLC 的新辅助治疗小型试验中显示出有趣的结果。此外，多项使用抗 PD-1/PD-L1 免疫疗法作为可切除分期 NSCLC 患者的辅助或新辅助治疗的临床试验正在进行中。然而，关于早期鳞状细胞肺癌 (SqCLC) 中抗 PD-1/PD-L1 免疫治疗相关生物标志物的分析报道很少。在这项研究中，我们评估了早期 SqCLC 中 PD-L1 蛋白的表达、肿瘤突变负荷和免疫基因特征的表达，为确定抗 PD-1/PD-L1 治疗患者在早期 SqCLC 中的潜在作用提供数据。方法：在战略合作评估癌症特征计划的参与中心内，共鉴定了 255 份来自早期 SqCLC 患者的标本。通过在 Dako Link 48 自动染色仪（Dako，Carpinteria，CA）上使用 Dako PD-L1 22C3 pharmDx 试剂盒，通过免疫组织化学评估 PD-L1 蛋白表达。基于靶向基因组测序的数据计算肿瘤突变负荷（TMB）。T 效应子和干扰素 γ (IFN-&ggr;) 基因特征是根据来自冷冻标本的 Affymetrix 基因芯片数据（Affymetrix，Santa Clara，CA）确定的。结果：在肿瘤比例评分临界值至少为 50% 时，PD-L1 表达的患病率为 9.8%。PD-L1 mRNA 和程序性细胞死亡 1 配体 2 mRNA 与肿瘤细胞 (TC) 和肿瘤浸润免疫细胞上的 PD-L1 蛋白表达呈正相关。肿瘤浸润免疫细胞上的 PD-L1 蛋白表达与 T 效应子和 IFN-&ggr 相关；基因特征 (p < 0.001)，但不是 TMB。对于 TC，所有这些生物标志物都相互独立，而且 PD-L1 蛋白表达、TMB 或 T 效应子和 IFN-> 基因特征是患者预后的独立预后因素。结论：对 PD-L1 表达、TMB 和 T 效应子和 IFN-&ggr 的评估；早期 SqCLC 队列中的基因特征发现它们彼此独立，并且与总生存率无关。