FAP and neoplasm: Depletion of CAFs using FAP-targeting has provided mixed results with FAP directed chimeric antigen receptor (CAR) T cells demonstrating severe toxicity with cachexia and bone marrow failure due to FAP expression in adipocytes and bone mesenchymal stem cells in one model[39], while others have demonstrated tumor growth delay due to enhanced CD8+ T cell function and persistence associated with decreased desmoplastic stroma[19–21].