具有表皮生长因子受体 (EGFR) 外显子 20 插入突变 (ex20ins) 的非小细胞肺癌 (NSCLC) 患者对免疫检查点抑制剂 (ICI) 单一疗法具有耐药性。然而，最近的报道表明，ICI与化疗联合（ICI-combined方案）对EGFR ex20ins的NSCLC表现出一定的疗效。这种现象背后的机制尚未彻底阐明。因此，我们开展本研究旨在寻找EGFR ex20ins的肿瘤免疫微环境与ICI联合方案疗效之间的相关性。我们通过单细胞转录组测序和多重免疫荧光染色（mIF）来研究EGFR ex20ins的NSCLC患者的免疫微环境、L858R 和 EGFR 野生型。我们利用单细胞 RNA 测序 (scRNA-seq) 分析了 15 个未经治疗的 NSCLC 样本。另外招募30例EGFR L858R和4例野生型，通过mIF将免疫微环境与EGFR ex20ins（28例）进行比较。我们观察到EGFR ex20ins、L858R和野生型之间的细胞成分、功能和相互作用存在差异。 - 型 NSCLC。我们发现各组之间的 T 细胞和 CD8 T 细胞分布相似，但发现 ex20ins 患者的 T 细胞激活程度不低甚至更好。与野生型相比，EGFR ex20ins 肿瘤区域的浸润 CD8 FOXP3- T 细胞显着降低。与野生型组相比，ex20ins 组的 T 细胞更容易促进癌细胞炎症和上皮间质转化 (EMT)。对于巨噬细胞，ex20ins患者中有更多的M2样巨噬细胞。 ex20ins组中的M1样巨噬细胞产生的抗肿瘤细胞因子比其他组少。EGFR ex20ins的免疫微环境比L858R和野生型的免疫微环境更具抑制性，表明ICI单一疗法可能不足以满足这些患者的需要。由于免疫微环境中促肿瘤炎症和非劣质 T 细胞功能，ICI 联合方案可能是 EGFR ex20ins 的一种治疗选择。版权所有 © 2024 作者。由 Elsevier B.V. 出版。保留所有权利。

Non-small cell lung cancer (NSCLC) patients with exon 20 insertion mutations (ex20ins) of the epidermal growth factor receptor (EGFR) were resistant to monotherapy of immune checkpoint inhibitor (ICI). However, recent reports have shown that the combination of ICI and chemotherapy (ICI-combined regimen) exhibited certain efficacy for NSCLC with EGFR ex20ins. The mechanisms behind this phenomenon have not been thoroughly clarified. Hence, we conducted this study tofind correlations between the tumor immune microenvironment of EGFR ex20ins and the efficacy of ICI-combined regimen.We performed single-cell transcriptome sequencing and multiplex immunofluorescence staining (mIF) to investigate the immune microenvironment of NSCLC patients with EGFR ex20ins, L858R, and EGFR wild-type. We analyzed 15 treatment-naïve NSCLC samples utilizing single-cell RNA sequencing (scRNA-seq). Another 30 cases of EGFR L858R and 4 cases of wild-type were recruited to compare the immune microenvironment with that of EGFR ex20ins (28 cases) by mIF.We observed that cell components, function and interactions varied between EGFR ex20ins, L858R, and wild-type NSCLC.We discovered similar T cell and CD8+ T cell distributions among groups but found noninferior or even better T cell activation in ex20ins patients. Infiltrating CD8+ FOXP3- T cells were significantly lower in the tumor region of EGFR ex20ins compared to wild-type. T cells from the ex20ins group had a greater tendency to promote cancer cell inflammation and epithelial-mesenchymal transition (EMT) compared to wild-type group. For macrophages, there were more M2-like macrophages in ex20ins patients. M1-like macrophages in ex20ins group produced fewer antitumor cytokines than in other groups.The immune microenvironment of EGFR ex20ins is more suppressive than that of L858R and wild-type, suggesting that ICI monotherapy may not be sufficient for these patients. ICI-combined regimen might be a treatment option for EGFR ex20ins due to tumor-promoting inflammation and noninferior T cell functions in the immune microenvironment.Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.