FAP and pancreatic neoplasm: The importance of an additional immunosuppressive cell type within the stroma was further defined through a recent study by Kraman et al. (2010), who demonstrated that a sub-population of stromal cells that express fibroblast activation protein (FAP) suppress the immune response and that abrogation of FAP expression arrests the growth of pancreatic tumors, potentially by removing their inhibitory effect on the host's immune response.