In order to determine whether CD3+ T cells are proliferating around ARG2-expressing CAFs in PDC tissue, we performed double immunohistochemistry for CD3 and Ki-67 and compared tumor-infiltrating CD3+ T cells with their proliferating index in the area around ARG2-expressing CAFs to the area within the tumor except for necrotic tissue. The gene discussed is ARG2; the disease is neoplasm.