The CD4+ T-lymphocytes secrete cytokines such as IL-1/2/6/8/10/12/17/18, TNF-α, IFN-γ, and GM-CSF, which in turn activate CD8+ cytotoxic T-cells, macrophages, neutrophils, and NKT-cells, or directly kill the BC cells such as IFN-γ [59]. This evidence concerns the gene CD8A and breast cancer.