This theory of immunoediting was developed only recently.36 TILs are considered to reflect immunoediting.37 TILs are observed in several tumor types, including colorectal cancer, gastric cancer, hepatocellular carcinoma, bile duct cancer, and pancreatic cancer, which are reported to have prognostic value.38 Regarding pancreatic cancer, Fukunaga et al39 first reported that both CD4+ and CD8+ TILs are associated with longer postoperative survival. The gene discussed is CD4; the disease is familial pancreatic carcinoma.