尽管嗜酸性粒细胞在肿瘤微环境中是免疫反应的一个重要组成部分，但只有少量研究揭示了嗜酸性粒细胞在癌症结果中的作用机制。嗜酸性粒细胞是一类少数粒细胞，主要在哮喘和过敏性疾病中得到研究。然而，近期发现它们对原发性和转移性肿瘤的影响。嗜酸性粒细胞具有多种介质和受体，使其能够参与先天性和适应性免疫，如1型和2型免疫，并塑造肿瘤微环境和肿瘤结果。根据肿瘤微环境细胞和细胞因子，活化的嗜酸性粒细胞驱动其他免疫细胞最终促进或抑制肿瘤生长。发现决定嗜酸性粒细胞促肿瘤活性或抗肿瘤活性的确切条件，使我们能够利用这些信号并设计新的靶向癌细胞的策略。在这里，我们首先重新审视嗜酸性粒细胞的生物学和分化，因为识别嗜酸性粒细胞介质对其在体内稳态和病理条件以及肿瘤结果中的功能至关重要。我们的论文的主要内容涵盖嗜酸性粒细胞与肿瘤细胞、免疫细胞（包括T细胞、浆细胞、自然杀伤细胞）和肠道微生物的相互作用。嗜酸性粒细胞介质，如IL-5、IL-33、粒细胞-巨噬细胞集落刺激因子（GM-CSF）、胸腺滤泡上皮淋巴样细胞因子（TSLP）和CCL11也决定了嗜酸性粒细胞对肿瘤细胞的反应。然后，我们探讨了这些发现对癌症免疫疗法的影响，包括使用免疫检查点阻断（ICB）疗法的免疫检查点抑制剂（ICI）和嵌合抗原受体（CAR）T细胞疗法。嗜酸性粒细胞与CAR T细胞和ICB疗法协同增强免疫疗法。 © 2023，BioMed Central Ltd. 是 Springer Nature 的一部分。

Despite being an integral part of the immune response in the tumor microenvironment (TME), few studies have mechanistically elucidated eosinophil functions in cancer outcomes. Eosinophils are a minor population of granulocytes that are mostly explored in asthma and allergic disorders. Their influence on primary and metastatic tumors, however, has recently come to light. Eosinophils' diverse armamentarium of mediators and receptors allows them to participate in innate and adaptive immunity, such as type 1 and type 2 immunity, and shape TME and tumor outcomes. Based on TME cells and cytokines, activated eosinophils drive other immune cells to ultimately promote or suppress tumor growth. Discovering exactly what conditions determine the pro-tumorigenic or anti-tumorigenic role of eosinophils allows us to take advantage of these signals and devise novel strategies to target cancer cells. Here, we first revisit eosinophil biology and differentiation as recognizing eosinophil mediators is crucial to their function in homeostatic and pathological conditions as well as tumor outcome. The bulk of our paper discusses eosinophil interactions with tumor cells, immune cells-including T cells, plasma cells, natural killer (NK) cells-and gut microbiota. Eosinophil mediators, such as IL-5, IL-33, granulocyte-macrophage colony-stimulating factor (GM-CSF), thymic stromal lymphopoietin (TSLP), and CCL11 also determine eosinophil behavior toward tumor cells. We then examine the implications of these findings for cancer immunotherapy approaches, including immune checkpoint blockade (ICB) therapy using immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cell therapy. Eosinophils synergize with CAR T cells and ICB therapy to augment immunotherapies.© 2023. BioMed Central Ltd., part of Springer Nature.