带有致癌基因 EML4-ALK 融合的肺癌对靶向酪氨酸激酶抑制剂（TKI，例如阿来替尼）做出反应，但在疗效缩小程度和治疗持续时间 (DOT) 方面存在差异。然而，控制该反应的因素仍不清楚。虽然免疫系统在介导免疫疗法反应方面的贡献得到了广泛研究，但对免疫对 TKI 治疗反应的贡献了解较少。我们之前证明了 TKI 诱导的干扰素γ (IFNγ) 转录反应与 EGFR 突变肺癌中 DOT 呈正相关。在这里，我们使用 EML4-ALK 肺癌的三个小鼠模型来测试宿主免疫在阿来替尼治疗反应中的作用。细胞系（EA1、EA2、EA3）在免疫能力正常和免疫缺陷小鼠的肺部原位增殖，然后用阿来替尼治疗。肿瘤体积通过微计算机断层扫描逐步测量，免疫细胞含量通过流式细胞术和多光谱免疫荧光测量。RNAseq 评估了对阿来替尼的转录反应，ELISA 测量了分泌的趋化因子。所有细胞系在体外和免疫能力正常小鼠的原位肿瘤上对阿来替尼的敏感性相似，并表现出持久的收缩。然而，在免疫缺陷小鼠中，所有肿瘤模型都迅速在 TKI 治疗中进展。在免疫能力正常的小鼠中，EA2 肿瘤表现出完全反应，而 EA1 和 EA3 肿瘤保留残留疾病，在 TKI 治疗终止后快速进展。在治疗之前，EA2 肿瘤与 EA1 肿瘤相比，具有更多的 CD8+ T 细胞和较少的中性粒细胞。此外，从未治疗的肿瘤中恢复的癌细胞的 RNAseq 结果显示，EA2 肿瘤中 CXCL9 和 10 的水平升高，而 EA1 肿瘤中 CXCL1 和 2 的水平更高。来自 ALK+ 肿瘤的治疗前患者活检分析表明，中性粒细胞含量与疾病进展时间缩短有关。总之，这些数据支持适应性免疫在 TKI 反应持久性中的作用，并证明肿瘤微环境中的免疫细胞组成预测了对阿来替尼治疗的反应。 ©2023年。作者（们）保留所有版权。

Lung cancers bearing oncogenic EML4-ALK fusions respond to targeted tyrosine kinase inhibitors (TKIs; e.g., alectinib), with variation in the degree of shrinkage and duration of treatment (DOT). However, factors that control this response are not well understood. While the contribution of the immune system in mediating the response to immunotherapy has been extensively investigated, less is known regarding the contribution of immunity to TKI therapeutic responses. We previously demonstrated a positive association of a TKI-induced interferon gamma (IFNγ) transcriptional response with DOT in EGFR-mutant lung cancers. Herein, we used three murine models of EML4-ALK lung cancer to test the role for host immunity in the alectinib therapeutic response. The cell lines (EA1, EA2, EA3) were propagated orthotopically in the lungs of immunocompetent and immunodeficient mice and treated with alectinib. Tumor volumes were serially measured by μCT and immune cell content was measured by flow cytometry and multispectral immunofluorescence. Transcriptional responses to alectinib were assessed by RNAseq and secreted chemokines were measured by ELISA. All cell lines were similarly sensitive to alectinib in vitro and as orthotopic tumors in immunocompetent mice, exhibited durable shrinkage. However, in immunodeficient mice, all tumor models rapidly progressed on TKI therapy. In immunocompetent mice, EA2 tumors exhibited a complete response, whereas EA1 and EA3 tumors retained residual disease that rapidly progressed upon termination of TKI treatment. Prior to treatment, EA2 tumors had greater numbers of CD8+ T cells and fewer neutrophils compared to EA1 tumors. Also, RNAseq of cancer cells recovered from untreated tumors revealed elevated levels of CXCL9 and 10 in EA2 tumors, and higher levels of CXCL1 and 2 in EA1 tumors. Analysis of pre-treatment patient biopsies from ALK+ tumors revealed an association of neutrophil content with shorter time to progression. Combined, these data support a role for adaptive immunity in durability of TKI responses and demonstrate that the immune cell composition of the tumor microenvironment is predictive of response to alectinib therapy.© 2023. The Author(s).