After comparing the fractions of 10 different immune cells (B cells, Macrophages M1, Macrophages M2, Monocytes, Neutrophils, Natural Killer (NK) cells, T cells CD4, T cells CD8, Tregs and dendritic cells) between tumors and matched histologically normal tissues, we found that the fractions of NK cells were significantly increased in both breast cancer subtypes. The gene discussed is CD4; the disease is breast cancer.