Abstract Antigen-presenting cancer-associated fibroblasts (apCAFs), commonly defined by MHC class II molecules, CD74, and related transcriptional programs, exhibit divergent functions across gastrointestinal tumors. In pancreatic ductal adenocarcinoma, mesothelium-derived apCAFs promote regulatory T-cell differentiation and suppress effector responses, whereas their abundance in gastric cancer is associated with earlier-stage disease, longer survival, and improved immunotherapy responses.
