Fibroblast activation protein (FAP), a type II membrane-bound glycoprotein of the dipeptidyl peptidase 4 family, is over-expressed in CAFs of many epithelial carcinomas and is involved in a variety of tumor-promoting activities, such as stromal remodeling, angiogenesis, chemotherapy resistance, and immunosuppression (1, 2). Here, FAP is linked to carcinoma.