In this study, a large number of animal experiments confirmed that CAG enhanced the effect of radiotherapy against brain metastasis tumors of lung cancer and reduced radiation damage of brain tumors by inhibiting neutrophil infiltration, and confirmed that CAG inhibited the expression of neutrophil chemotactic-related cytokines such as CXCL3 and CCL5 by inhibiting the activity of the JAK/STAT signaling pathway in LLC brain tumors. The gene discussed is CXCL3; the disease is lung cancer.