PDCD1 and gastric adenocarcinoma: In the present study, we also focused on PD-1, Tim-3, and Lag-3 axes because CEACAM-1 (ligand for Tim-3) was highly expressed in gastric adenocarcinoma tissues but not in normal gastric mucosa [18], and gastroesophageal tumor samples had higher expression of LSECtin (ligand for Lag-3) than corresponding adjacent normal tissues [19], and expression of MHC class II (ligand for Lag-3) on solid tumor cells was found to have negative impact by promoting T cell anergy [20].