FAP and gastric adenocarcinoma: In the current study, FAP expression was positively linkded to the infiltration levels of eosinophils, monocytes, M1 macrophages, resting mast cells, M2 macrophages, and neutrophils in STAD, while infiltration levels of several immune cells, including naïve B cells and CD4+ resting memory T cells, were inversely linked to the expression of FAP.