While the extent of liver metastasis appeared to occur independent of the immune system, we discovered an inverse correlation between the density of CD45+ (R2 = 0.868), CD3+ (R2 = 0.726), and especially CD8+ cell (R2 = 0.997) in the primary tumor and the extent of lung MDA‐MB‐231 lung metastases (Fig. 3A–C). The gene discussed is CD8A; the disease is neoplasm.