MSLN and pancreatic neoplasm: Antigen-presenting CAFs (apCAFs) are developed from mesothelial cells, which process activated by interleukin-1 and TGF-β, and apCAFs could stimulate regulatory T cells (Tregs) formation in pancreatic cancer, moreover, the process of mesothelial cells to apCAFs transition and Tregs formation induced by apCAFs could be inhibited by the antibody targeting mesothelin, which is one of the mesothelial cell markers [33].