Among TILs, CD4+ T cells, CD4+ naïve T cells, CD8+ T cells, eosinophils, and mast cells were found to be significantly enriched in breast cancer patients without lung metastasis, while pro B cells, neutrophils, and Th2 cells were significantly enriched in breast cancer patients with lung metastasis (Figure 1C). This evidence concerns the gene CD4 and breast cancer.