In one study, 145 pancreatic cancer patients who had undergone pancreatectomy followed by postoperative chemotherapy (mostly Gemcitabine) were tested for TIL number and their distribution in relation to expression of PD-1, its ligand (PD-L1; expressed on macrophages, epithelial and other normal cells), as well as CD8 and FOXP3 in tumor-infiltrating leukocytes [135]. The gene discussed is PDCD1; the disease is pancreatic neoplasm.