Neutrophils are known to contribute in many aspects of tumor progression and metastasis. The presence of neutrophils or neutrophil-derived mediators in the tumor microenvironment has been associated with poor prognosis in several types of solid tumors. However, the effects of classical cancer treatments such as radiation therapy on neutrophils are poorly understood. Furthermore, the cellular composition and distribution of immune cells in the tumor is of increasing interest in cancer research and new imaging technologies allow to perform more complex spatial analyses within tumor tissues. Therefore, we aim to offer novel insight into intra-tumoral formation of cellular neighborhoods and communities in murine breast cancer. To address this question, we performed image mass cytometry on tumors of the TS/A breast cancer tumor model, performed spatial neighborhood analyses of the tumor microenvironment and quantified neutrophil-extracellular trap degradation products in serum of the mice. We show that irradiation with 2 × 8 Gy significantly alters the cellular composition and spatial organization in the tumor, especially regarding neutrophils and other cells of the myeloid lineage. Locally applied radiotherapy further affects neutrophils in a systemic manner by decreasing the serum neutrophil extracellular trap concentrations which correlates positively with survival. In addition, the intercellular cohesion is maintained due to radiotherapy as shown by E-Cadherin expression. Radiotherapy, therefore, might affect the epithelial–mesenchymal plasticity in tumors and thus prevent metastasis. Our findings underscore the growing importance of the spatial organization of the tumor microenvironment, particularly with respect to radiotherapy, and provide insight into potential mechanisms by which radiotherapy affects epithelial–mesenchymal plasticity and tumor metastasis.

已知中性粒细胞在肿瘤进展和转移的许多方面都有贡献。肿瘤微环境中中性粒细胞或中性粒细胞衍生介质的存在与多种类型实体瘤的不良预后相关。然而，人们对放射治疗等经典癌症治疗对中性粒细胞的影响知之甚少。此外，肿瘤中免疫细胞的细胞组成和分布越来越受到癌症研究的关注，新的成像技术允许在肿瘤组织内进行更复杂的空间分析。因此，我们的目标是对小鼠乳腺癌细胞邻域和群落的瘤内形成提供新的见解。为了解决这个问题，我们对 TS/A 乳腺癌肿瘤模型的肿瘤进行了图像质量细胞术，对肿瘤微环境进行了空间邻域分析，并对小鼠血清中的中性粒细胞外捕获降解产物进行了定量。我们发现，2 × 8 Gy 的照射显着改变了肿瘤中的细胞组成和空间组织，特别是中性粒细胞和骨髓谱系的其他细胞。局部放疗通过降低与生存呈正相关的血清中性粒细胞胞外陷阱浓度，进一步以全身方式影响中性粒细胞。此外，如 E-钙粘蛋白表达所示，由于放射治疗，细胞间凝聚力得以维持。因此，放射治疗可能会影响肿瘤的上皮间质可塑性，从而防止转移。我们的研究结果强调了肿瘤微环境的空间组织日益重要，特别是在放射治疗方面，并提供了对放射治疗影响上皮间质可塑性和肿瘤转移的潜在机制的见解。